Entire Report - Annual 2012


National Overview

NCDC transitioned to the nClimDiv dataset on Thursday, March 13, 2014. This was coincident with the release of the February 2014 monthly monitoring report. For details on this transition, please visit our public FTP site and our U.S. Climate Divisional Database site.

Issued January 8, 2013: The data presented in this report are final through July and preliminary from August-December. Ranks, anomalies, and percent areas may change as more complete data are received and processed.

Collapse ↑
Note: GHCN-M Data Notice

An omission in processing a correction algorithm led to some small errors on the Global Historical Climatology Network-Monthly dataset (GHCN-M v3.2.0). This led to small errors in the reported land surface temperatures in the October, November, December and Annual U.S. and global climate reports. On February 14, 2013, NCDC fixed this error in its software, included an additional improvement (described below), and implemented both changes as GHCN-M version 3.2.1. With this update to GHCN-M, the Merged Land and Ocean Surface Temperature dataset also is subsequently revised as MLOST version 3.5.3.

The net result of this new version of GHCN-M reveals very small changes in temperature and ranks. The 2012 U.S. temperature is 0.01°F higher than reported in early January, but still remains approximately 1.0°F warmer than the next warmest year, and approximately 3.25°F warmer than the 20th century average. The U.S. annual time series from version 3.2.1 is almost identical to the series from version 3.2.0 and that the 1895-2012 annual temperature trend remains 0.13°F/decade. The trend for certain calendar months changed more than others (discussed below). For the globe, ranks of individual years changed in some instances by a few positions, but global land temperature trends changed no more than 0.01°C/century for any month since 1880.

NCDC uses two correction processes to remove inhomogeneities associated with factors unrelated to climate such as changes in observer practices, instrumentation, and changes in station location and environment that have occurred through time. The first correction for time of observation changes in the United States was inadvertently disabled during late 2012. That algorithm provides for a physically based correction for observing time changes based on station history information. NCDC also routinely runs a .pairwise correction. algorithm that addresses such issues, but in an indirect manner. It successfully corrected for many of the time of observation issues, which minimized the effect of this processing omission.

The version 3.2.1 release also includes the use of updated data to improve quality control and correction processes of other U.S. stations and neighboring stations in Canada and Mexico.

Compared to analyses released in January 2013, the trend for certain calendar months has changed more than others. This effect is related to the seasonal nature of the reintroduced time-of-observation correction. Trends in U.S. winter temperature are higher while trends in summer temperatures are lower. For the globe, ranks of individual years changed in some instances by a few positions, but global temperature trends changed no more than 0.01°C/century for any month since 1880.

More complete information about this issue is available at this supplemental page.

NCDC will not update the static reports from October through December 2012 and the 2012 U.S and Global annual reports, but will use the current dataset (GHCN-M v. 3.2.1 and MLOST v. 3.5.3) for the January 2013 report and other comparisons to previous months and years.

Collapse ↑

National Temperature and Precipitation Analysis


Supplemental 2012 Temperature and Precipitation Information

In 2012, the contiguous United States (CONUS) average annual temperature of 55.3°F was 3.2°F above the 20th century average, and was the warmest year in the 1895-2012 period of record for the nation. The 2012 annual temperature was 1.0°F warmer than the previous record warm year of 1998. Since 1895, the CONUS has observed a long-term temperature increase of about 0.13°F per decade. Precipitation averaged across the CONUS in 2012 was 26.57 inches, which is 2.57 inches below the 20th century average. Precipitation totals in 2012 ranked as the 15th driest year on record. Over the 118-year period of record, precipitation across the CONUS has increased at a rate of about 0.16 inch per decade.

On a statewide and seasonal level, 2012 was a year of both temperature and precipitation extremes for the United States. Each state in the CONUS had annual temperatures which were above average. Nineteen states, stretching from Utah to Massachusetts, had annual temperatures which were record warm. An additional 26 states had one of their 10 warmest years. Only Georgia (11th warmest year), Oregon (12th warmest), and Washington (30th warmest) had annual temperatures that were not among the ten warmest in their respective period of records. A list of the annual temperatures for each of the lower-48 states is available here. Numerous cities and towns were also record warm during 2012 and a select list of those locations is available here. Each state in the CONUS, except Washington, had at least one location experience its warmest year on record. One notable warmest year record occurred in Central Park, in New York City, which has a period of record dating back 136 years.

Much of the CONUS was drier than average for the year. Below-average precipitation totals stretched from the Intermountain West, through the Great Plains, into the Midwest and Southeast. Nebraska and Wyoming were both record dry in 2012. Nebraska’s annual precipitation total of 13.04 inches was 9.78 inches below average, and Wyoming’s annual precipitation total of 8.08 inches was 5.09 inches below average. New Mexico, Colorado, Kansas, Missouri, Illinois, Arkansas, Georgia, and Delaware had a top ten dry year. The large area of dry conditions in 2012 resulted in a very large footprint of drought conditions, which peaked in July with about 61 percent of the CONUS in moderate-to-exceptional drought, according to the Palmer Drought Severity Index (PDSI). The footprint of drought during 2012 roughly equaled the drought of the 1950s which peaked at approximately 60 percent. Wetter-than-average conditions were present for the Northwest, where Washington had its fifth wettest year on record. Washington’s statewide precipitation total of 47.24 inches was 10.40 inches above average. Wetter-than-average conditions were also present across parts of the Gulf Coast and Northeast.

Seasonal highlights in 2012 include the fourth warmest winter (December 2011-February 2012), with warmer-than-average conditions across a large portion of the country. The largest temperature departures from average were across the Northern Plains, Midwest, Mid-Atlantic, and Northeast. Winter was drier than average for the East and West coasts, while the Southern Plains were wetter than average improving drought conditions across New Mexico, Oklahoma, and Texas. The warmer and drier than average conditions resulted in the third smallest winter snow cover extent on record for the contiguous United States. Spring (March-May) was record warm for the country, with 34 states being record warm for the period. The season consisted of the warmest March, fourth warmest April, and second warmest May on record. Spring precipitation was near-average for the lower-48, with the Pacific Northwest and Upper Midwest being wetter than average, while the Central Rockies and Ohio Valley were drier than average. The summer (June-August) continued the warmer-than-average trend for the contiguous U.S. with national temperatures ranking as the second warmest on record. The summer average temperature for 2012 was very close to the warmest summer (2011) and the third warmest summer (1936), with only 0.1°F separating the three. The summer season consisted of the eighth warmest June, record warmest July, and 13th warmest August. Drier-than-average conditions were anchored in the central U.S. with record breaking wildfires and a drought footprint comparable to the drought episodes of the 1950s causing large-scale agriculture problems in the Midwest, Plains, and Mountain West. Autumn (September-November) temperatures were closer to average compared to the preceding three seasons, but still ranked as the 22nd warmest autumn on record. Warmer-than-average conditions were present for the West, while cooler-than-average conditions were present for the Eastern Seaboard. Precipitation totals for the nation averaged as the 22nd driest autumn on record.

This annual report places the temperature and precipitation averages into historical perspective, while summarizing the notable events that occurred in 2012. More detailed analysis on individual months can be found through the Climate Monitoring home page.


Top Ten U.S. Weather/Climate Events for 2012

The following is a list for the top ten U.S. weather/climate events which occurred during 2012. These events were selected by a panel of weather/climate experts from around the country.

Rank Event
1 Hurricane/Post-Tropical Storm Sandy
2 Contiguous U.S. Drought
3 Contiguous U.S. Warmest Year on Record
4 Record Wildfire Activity
5 Multi-State Derecho
6 March 2nd-3rd Severe Weather Outbreak
7 Alaska Cold Winter/Snow Records
8 Near-Record Low Great Lakes Levels
9 Contiguous U.S. Snow Cover
10 Hurricane Isaac

Seasonal Analysis


Winter

The 2011/12 winter season was marked by above-average temperatures for a large portion of the nation, stretching from the Rockies, through the Plains, and along the East Coast. The Northern Plains, Midwest, and Northeast had the largest temperature departures from average for the season. The CONUS had an average winter temperature of 36.4°F, which was 3.8°F above the 20th century average and was the fourth warmest winter on record. In total, 22 states had December-February temperatures ranking among their ten warmest and four states in the West had winter temperatures which were near-normal. This winter season contrasted with the previous two winters for the CONUS (2009/10 and 2010/11) which ranked as the 14th and 34th coldest winter seasons, respectively. The 2009/10 and 2010/11 winters were marked by record and near-record negative phases of the North Atlantic (NAO) and Arctic (AO) oscillations, which were associated with frequent and long-lasting cold-air outbreaks. The 2011/12 winter had the opposite configuration of the NAO and AO. The NAO averaged for December 2011 was +2.52, the largest positive phase of the index for a month on record. When the NAO and AO are in a positive phase during the winter, the jet stream, which divides cold Arctic air to the north and warm sub-tropical air to the south, tends to remain north of the U.S.-Canadian border. This was the case for the 2011/12 winter which was marked by few and short-lived cold air outbreaks in the CONUS.

The presence of La Niña during the winter had a minimal influence on precipitation patterns during the season. The 3-month average CONUS precipitation of 5.77 inches was 0.70 inch below average. The western U.S. was drier than average, where California had its third driest winter on record, with a statewide precipitation total of 4.09 inches, 7.82 inches below average. Drier-than-average conditions stretched across the Northern Plains into the Upper Midwest. Much of the Eastern Seaboard was also drier than average, where North Carolina had its ninth driest winter and South Carolina its sixth driest. The warm and dry conditions during winter limited snow across a large portion of the country, and the CONUS had its third smallest seasonal snow cover since satellite records began 46 years ago. Many of the major cities in the Northeast and Midwest had record and near-record low seasonal snowfall. Wetter-than-average conditions occurred in the Southern Plains, where Texas had its tenth wettest winter with a precipitation total of 7.63 inches, 2.50 inches above average. The above-average winter precipitation in Texas helped to improve drought conditions which plagued the state during much of 2011. Above-average precipitation was also present for parts of Ohio Valley. The drier-than-average conditions observed along the East Coast and wetter-than-average conditions in the Ohio Valley are consistent with La Niña, but the winter wetness in the Southern Plains is more typical of an El Niño, not a La Niña.

Spring

The spring (March-May) of 2012 was marked by record warmth over a large portion of the country. The CONUS average temperature for the season was 56.1°F, 5.2°F above the 20th century average, and the warmest spring on record, by 2.0°F. The previous record warm spring occurred in 1910 with a seasonally averaged temperature of 54.1°F. Spring 2012 also marked the largest warm temperature departure from average for any season on record for the CONUS. All three months of the season ranked among their five warmest, also a first for the nation. The March average temperature was 8.6°F above average and the record warmest March, April was 3.6°F above average and the fourth warmest April, and May was 3.5°F above average, the second warmest May on record. Thirty-four states0 were record warm for spring, all east of the Rockies, while an additional eight states were top ten warm. The U.S. Climate Extremes Index (USCEI) was record large for the season, driven mostly by the large footprint in extremely warm daytime and warm nighttime temperatures. Numerous states, mostly across the Midwest, had spring temperatures more than 7.0°F above average. Only Oregon and Washington had seasonal temperatures near normal.

The spring CONUS precipitation total of 7.32 inches was 0.39 inch below average and ranked near the median value. The near-average CONUS precipitation total masked regional extremes on both the wet and dry ends of the spectrum. The Pacific Northwest was bombarded by numerous storms during the spring season, resulting in Oregon and Washington having seasonal precipitation totals among their ten wettest. The active storm pattern resulted in above-average snowpack for the Cascades of Oregon and Washington, with near-normal snowpack stretching eastward through the northern Rockies of Idaho, Montana, and northern Wyoming. The Upper Midwest was also wetter than average, where Minnesota had its third wettest spring. Below-average precipitation totals were centered in the central Rockies and the Ohio Valley. Colorado, Utah, and Wyoming each had a top ten dry spring season, where below-average snowpack resulted. In the Ohio Valley, Indiana and Tennessee both had a top ten dry spring. The below-average precipitation in the Midwest was accompanied by below-average tornado activity, despite a few deadly tornado outbreaks. The warm and dry spring, in combination with other factors, played precursor to the large expansion of drought which impacted the nation during the summer of 2012.

Summer

The summer (June-August) of 2012 brought a continuation of warmer-than-average conditions for a large area of the CONUS. The summer’s average temperature for the CONUS was 73.8°F, 2.6°F above the 20th century average and the second warmest summer on record. Only the summer of 2011 was warmer. Above-average temperatures were present for the Rockies, Great Plains, Midwest, Northeast, and much of the West, with the exception of Washington State. The Southeast had near-normal summer temperatures. Colorado and Wyoming each had their warmest summer on record, with 3-month average temperatures 4.9°F and 4.6°F above average, respectively. Twenty-one additional states had summer temperatures among their ten warmest. During the summer, at least 357 all-time hot daytime temperature records were broken, including a new all-time state record for South Carolina (113.0°F). During the summer period, approximately 99.1 million Americans experienced at least 10 days with daytime temperatures exceeding 100.0°F — nearly one third of the country's population. In addition to the warm summer, the period from August 2011 through July 2012 was the warmest consecutive 12 months that the nation has observed.

In addition to the summer being hot for a large part of the country, it was also dry, resulting in a drought footprint comparable to the drought episodes of the 1950s. The drought peaked in July, when according to the Palmer Drought Severity Index (PDSI), the spatial area of the CONUS in at least moderate drought was 61.8 percent. The summer CONUS precipitation total of 7.22 inches was 1.03 inches below average and the 14th driest summer on record. The epicenter of the drought stretched from the Rockies through the Great Plains and into the Midwest. Wyoming and Nebraska had their driest summer on record with precipitation totals 44 percent and 39 percent of average, respectively. Six additional states had summer precipitation totals among their ten driest. The hot and dry conditions also caused significant wildfire activity across the nation. The 7.0 million acres which burned during the three summer months was the second most in the 13-year record, slightly behind the summer of 2005. The West Coast was slightly wetter than average during the summer, where an active storm pattern in the Northwest, and an active monsoonal flow in the Southwest kept conditions wet. The Gulf Coast was wetter than average, with Florida having its wettest summer on record with a seasonal precipitation total 140 percent of average. The summer wetness along the Gulf Coast was partially attributable to Hurricane Isaac in August and Tropical Storm Debby in June. The Northeast was also wetter than average.

Fall

The CONUS average temperature for autumn (September-November) was 54.7°F which was 1.1°F above average. During the season, cooler-than-average conditions were present from the Midwest and Mid-Atlantic into the Southeast and Gulf Coast. Kentucky had its sixth coolest autumn with seasonal temperatures 2.5°F below average, and Mississippi had its 10th coolest with temperatures 2.2°F below average. The cool temperatures in the East were counterbalanced by warmth in the West. Arizona, California, Idaho, New Mexico, Utah, and Wyoming each had a top ten warm season. Nevada had its warmest autumn on record with a statewide average temperature of 53.8°F which was 3.7°F above average. Despite the seasonal temperature being above average, the October CONUS temperature was 0.3°F below average, ending a 16-month streak of above-average temperatures for the lower 48 that began in June 2011. The 16 consecutive months of above-average temperatures for the CONUS was the longest such streak on record.

The autumn precipitation for the lower-48 was 1.00 inch below average at 5.71 inches. Drier-than-average conditions persisted for the central parts of the country, where Minnesota, Nebraska, and South Dakota each had a top ten dry season. Dry conditions were also present for the Southeast coast, Southern Plains, the Southwest, and Central Rockies. The dryness during autumn, combined with the drier than average conditions during much of 2012, were associated with the western Great Lakes approaching record low water levels. The drought also hit the Lower Mississippi River hard, where near-record low water levels drastically slowed commercial shipping. Washington State, as well as parts of the Midwest, Mid-Atlantic, and Northeast, were wetter than average. Post-tropical cyclone Sandy, which slammed into the New Jersey coast in late October, brought heavy rains to the Northeast and heavy snowfall to the Central Appalachians.

[ top ]


Alaska Annual Summary

Alaska temperatures in 2012 were below the 1971-2000 average. The annual temperature for Alaska was 2.3°F below average, which ranked as the 11th coolest year on record for the state. Alaska had its coldest January on record with a statewide temperature 14.0°F below average and statewide temperatures remained cooler than average for much of the rest of 2012. Winter temperatures (December 2011-February 2012) were 1.4°F below the 1971-2000 average, spring temperatures were 2.7°F below average, summer temperatures were 0.7°F below average, and autumn temperatures were 1.1°F below average.

Precipitation across Alaska in 2012 was 9.2 percent above average and the 35th wettest year on record for the state. Alaska had its 12th wettest winter on record with a statewide precipitation total 42.6 percent above average. Several winter storms impacted the state over the course of the season and numerous locations broke seasonal snowfall records, including Anchorage with 134.5 inches. Spring precipitation was 10.5 percent above average, summer precipitation was 19.3 percent above average, and autumn precipitation was 11.6 percent above average. During the autumn season, several large storms hit the state bringing heavy rain to the southern coasts and snowfall to the high elevations. September was the fifth wettest such month on record, with a statewide precipitation total 48.1 percent above average.


Very Warm/Cold and Wet/Dry Percentages

One way to assess the magnitude of warm/cold and wet/dry episodes is to compute the percent area of the contiguous United States that was "very warm/very cold" and that which was "very wet/very dry". The figures above depict these values for each month in the past 30 years. These percentages are computed based on the climate division data set. Those climate divisions having a monthly average temperature/precipitation in the top ten percent (> 90th percentile) of their historical distribution are considered "very warm/very wet" and those in the bottom ten percent (< 10th percentile) are "very cold/very dry". The “very warm” categories translate to the “much above average” while the “very cold” categories translate to the “much below average” in terms of the NCDC ranking methods. This is similar for the “very wet” and “very dry” categories and the NCDC ranking methods of precipitation totals.

During 2012, the U.S. experienced its fourth warmest winter, a record warm spring, second warmest summer, and a warmer-than-average autumn. The warmer-than-average seasons resulted in large percentages of the country ranking as “very warm” and very small percentages ranking as “very cold” for most of the months during 2012. The table below shows the percent area of the nation “very warm” and “very cold” for each month of 2012 as well as the annual averaged values.

Month Percent area of CONUS "very warm" Percent area of CONUS "very cold"
January 28.8 0.0
February 12.9 0.0
March 75.4 0.4
April 43.2 0.0
May 48.6 0.0
June 28.7 2.6
July 60.40.0
August 28.9 1.1
September 14.6 0.1
October 1.2 3.1
November 26.6 3.6
December 20.0 0.3
2012 32.5 0.9

During 2012, large portions of the nation were drier than average, but areas of the country were also wetter than average. Each season had CONUS precipitation totals below average. The table below shows the percent area of the nation “very wet” and “very dry” for each month of 2012 as well as the annual averaged values.

Month Percent area of CONUS "very wet" Percent area of CONUS "very dry"
January 2.3 8.2
February 6.6 8.4
March 16.410.6
April 4.110.2
May 6.120.0
June 6.633.1
July 8.312.2
August 6.421.4
September 5.424.8
October 9.74.5
November 2.136.2
December 9.9 2.7
2012 7.0 16.0

[ top ]


Climate Extremes Index

The U.S. Climate Extremes Index (USCEI) measures the occurrence of several types of climate extremes, such as record or near-record warmth, dry spells or rainy periods. In 2012, extremes in warm temperatures as well as extensive drought conditions persisted across the country. Drought conditions overwhelmed much of the central portion of the contiguous U.S. (CONUS) and grew as large as areas of drought from the 1950s during the summer months of 2012. Record to near-record heat beginning in March led to the warmest year on record for the CONUS. The spatial extent of extremes, as measured by the USCEI, during the calendar year was 19 percent greater than the historical average and the second largest extent in combined extremes on record (since 1910). This record extent of extremes was primarily the result of extremes in warm maximum and minimum temperatures as well as large areas of dryness, as denoted by the Palmer Drought Severity Index (PDSI). Regions that experienced some of the most wide-spread extremes during 2012 include the Southwest, Northern Rockies and Plains, Upper Midwest, South, Ohio Valley and the Northeast. During 2012, the most prominent and wide-spread extremes occurred during: spring and summer.

Spring 2012 Regional CEI Map
Regional CEI values for spring 2012

At the national level, nearly half of the U.S. experienced a combination of extremes in the spring, primarily resulting from exceptionally warm maximum and minimum temperatures and drought conditions. March temperatures across the Upper Mississippi Valley, Great Lakes and into the Northeast were comparable to average May temperatures and were more than 10°F warmer than average. Drought conditions began to expand across much of the central Great Plains as warm temperatures conspired with low spring rainfall and a relatively snow-free winter, to leave soils parched.

For the CONUS, the spatial extent of the CEI was approximately 25 percent greater than the historical average during spring, a record extent for the season. Factors contributing to this record spring value were large footprints of warm maximum and warm minimum temperatures as well as areas of extreme PDSI dryness. Warm extremes blanketed the eastern three-quarters of the CONUS with all or nearly all of the Upper Midwest, Northeast, Ohio Valley, Southeast and South regions experiencing extremes in both maximum and minimum temperatures. In fact, the South and the Southeast regions had their largest extent of combined extremes on record with 52 percent and 53 percent of each region affected during this season, respectively.

Summer 2012 Regional CEI Map
Regional CEI values for summer 2012

The summer season was second warmest on record for the CONUS with above average temperatures extending from the Southwest though the Rocky Mountain and High Plains states and into the Great Lakes region. Precipitation received from Hurricane Isaac in August helped mitigate drought conditions across portions of Arkansas, Missouri and into parts of southern Illinois. The CEI for the contiguous U.S. was approximately 12 percent greater than the historical average during summer. This above-average extent was due primarily to record extent of extremes in warm maximum temperature, nearly four times the average extent of warm minimum temperatures, and more than a third of the country experiencing extremes in PDSI dryness.


NOAA's National Climatic Data Center is the world's largest active archive of weather data. The preliminary temperature and precipitation rankings are available from the center by calling: 828-271-4800.

NOAA works closely with the academic and science communities on climate-related research projects to increase the understanding of El Niño and improve forecasting techniques. NOAA's Climate Prediction Center monitors, analyzes and predicts climate events ranging from weeks to seasons for the nation. NOAA also operates the network of data buoys and satellites that provide vital information about the ocean waters, and initiates research projects to improve future climate forecasts.

Global Analysis

Note: On January 15, 2012, NCDC announced as part of its 2012 Global Climate Report that 2012 was the warmest La Niña year on record. While there are a variety of approaches for defining a La Niña or El Niño year, NCDC's criteria is defined as when the first three months of a calendar year meet the La Niña or El Niño threshold as defined by NOAA Climate Prediction Center's (CPC) Oceanic Niño Index (ONI). The list of historical La Niña years released on January 15 was based on an ONI dataset in force in early 2012 and used a 1971–2000 base period. During the course of the year, CPC introduced an ONI dataset using different base periods for determining anomalies for each year, with the most recent years (1995 to date) utilizing the 1981–2010 base period. Because of long-term warming trends in the equatorial Pacific Ocean, applying this more recent base period allows for better discernment of the temperature patterns needed to identify El Niño and La Niña years. In the most recent version of the dataset, using the newer base period methodology, 2006 and 2009 are now classified as La Niña years. The global average temperature in both 2006 and 2009 was 0.02°C (0.04°F) higher than 2012, making these two years the warmest La Niña years on record. NCDC has updated (via strikeout) our Annual Global Climate report to reflect the most current CPC ONI dataset.

With binary definitions of El Niño or La Niña, small changes in processing the data can affect the classification of weak El Niños or La Niñas. Despite these reclassifications, the general conclusions are similar from previous work: (1) global temperature anomalies for each phase (El Niño, La Niña, and neutral) have been increasing over time and (2) on average, global temperatures during El Niño years are higher than neutral years, which in turn, are higher than La Niña years.

NCDC continually examines its practices and definitions as science, datasets, and the understanding they bring improve. Thus, given the nature of our current method of classifying years as El Niño or La Niña, NCDC plans to re-examine and employ the best available definitions and datasets to robustly characterize the influence of El Niño and LaNiña on annual global temperatures.


Collapse ↑
Note: GHCN-M Data Notice

An omission in processing a correction algorithm led to some small errors on the Global Historical Climatology Network-Monthly dataset (GHCN-M v3.2.0). This led to small errors in the reported land surface temperatures in the October, November, December and Annual U.S. and global climate reports. On February 14, 2013, NCDC fixed this error in its software, included an additional improvement (described below), and implemented both changes as GHCN-M version 3.2.1. With this update to GHCN-M, the Merged Land and Ocean Surface Temperature dataset also is subsequently revised as MLOST version 3.5.3.

The net result of this new version of GHCN-M reveals very small changes in temperature and ranks. The 2012 U.S. temperature is 0.01°F higher than reported in early January, but still remains approximately 1.0°F warmer than the next warmest year, and approximately 3.25°F warmer than the 20th century average. The U.S. annual time series from version 3.2.1 is almost identical to the series from version 3.2.0 and that the 1895-2012 annual temperature trend remains 0.13°F/decade. The trend for certain calendar months changed more than others (discussed below). For the globe, ranks of individual years changed in some instances by a few positions, but global land temperature trends changed no more than 0.01°C/century for any month since 1880.

NCDC uses two correction processes to remove inhomogeneities associated with factors unrelated to climate such as changes in observer practices, instrumentation, and changes in station location and environment that have occurred through time. The first correction for time of observation changes in the United States was inadvertently disabled during late 2012. That algorithm provides for a physically based correction for observing time changes based on station history information. NCDC also routinely runs a .pairwise correction. algorithm that addresses such issues, but in an indirect manner. It successfully corrected for many of the time of observation issues, which minimized the effect of this processing omission.

The version 3.2.1 release also includes the use of updated data to improve quality control and correction processes of other U.S. stations and neighboring stations in Canada and Mexico.

Compared to analyses released in January 2013, the trend for certain calendar months has changed more than others. This effect is related to the seasonal nature of the reintroduced time-of-observation correction. Trends in U.S. winter temperature are higher while trends in summer temperatures are lower. For the globe, ranks of individual years changed in some instances by a few positions, but global temperature trends changed no more than 0.01°C/century for any month since 1880.

More complete information about this issue is available at this supplemental page.

NCDC will not update the static reports from October through December 2012 and the 2012 U.S and Global annual reports, but will use the current dataset (GHCN-M v. 3.2.1 and MLOST v. 3.5.3) for the January 2013 report and other comparisons to previous months and years.

Collapse ↑

Contents of this Section:



Global Highlights

  • The year 2012 was the 10th warmest year since records began in 1880. The annual global combined land and ocean surface temperature was 0.57°C (1.03°F) above the 20th century average of 13.9°C (57.0°F). This marks the 36th consecutive year (since 1976) that the yearly global temperature was above average. Currently, the warmest year on record is 2010, which was 0.66°C (1.19°F) above average. Including 2012, all 12 years to date in the 21st century (2001–2012) rank among the 14 warmest in the 133-year period of record. Only one year during the 20th century—1998—was warmer than 2012.

  • Separately, the 2012 global average land surface temperature was 0.90°C (1.62°F) above the 20th century average of 8.5°C (47.3°F) and ranked as the seventh warmest year on record.

  • La Niña, which is defined by cooler-than-normal waters in the eastern and central equatorial Pacific Ocean that affect weather patterns around the globe, was present during the first three months of 2012. The weak-to-moderate La Niña dissipated in the spring and was replaced by ENSO-neutral conditions for the remainder of the year. When compared to previous La Niña years, the 2012 global surface temperature was the warmest observed during such a year; 2011 was the previous warmest La Niña year on record. When compared to previous La Niña years, the 2012 global surface temperature was the third warmest observed during such a year, behind 2006 and 2009, which are currently tied for warmest.

  • The 2012 global average ocean temperature was 0.45°C (0.81°F) above the 20th century average of 16.1°C (60.9°F) and ranked as the 10th warmest year on record. It was also the warmest year on record among all La Niña years. The three warmest annual ocean surface temperatures occurred in 2003, 1998, and 2010—all warm phase El Niño years.

  • Following the two wettest years on record (2010 and 2011), 2012 saw near average precipitation on balance across the globe. However, as is typical, precipitation varied greatly from region to region.



Global Temperatures

The year 2012 was the 10th warmest year since records began in 1880. The annually-averaged temperature across global land and ocean surfaces was 0.57°C (1.03°F) above the 20th century average. Record to near-record warm land surface temperatures in the Northern Hemisphere from April to September and overall warmer-than-average ocean surface temperatures made the first 11 months of the year the eighth warmest January–November on record. However, extreme cold across much of the Northern Hemisphere land during December helped lower the year-to-date temperature departure from average by 0.02°C (0.04°F) compared with the previous month.

Year-to-Date Temperature Anomalies: Horserace
Year-to-date temperatures by month, with 2012 compared to the five warmest years on record

2012 marks the 36th consecutive year (since 1976) that the annual temperature was above the long-term average. Currently, the warmest year on record is 2010, which was 0.66°C (1.19°F) above average. Including 2012, all 12 years to date in the 21st century (2001–2012) rank among the 14 warmest in the 133-year period of record. Only one year during the 20th century—1998—was warmer than 2012. The global annual temperature has increased at an average rate of 0.06°C (0.11°F) per decade since 1880 and at an average rate of 0.16°C (0.28°F) per decade since 1970.

Top 10 Warmest Years (1880–2012)

The following table lists the global combined land and ocean annually-averaged temperature rank and anomaly for each of the 10 warmest years on record.

Rank
1 = Warmest
Period of Record: 1880–2012
Year Anomaly °C Anomaly °F
1 2010 0.66 1.19
2 2005 0.65 1.17
3 1998 0.63 1.13
4 2003 0.62 1.11
5 2002 0.61 1.10
6 (tie)* 2006 0.59 1.07
6 (tie)* 2009 0.59 1.07
6 (tie)* 2007 0.59 1.06
9 2004 0.58 1.04
10 2012 0.57 1.03
*Note: Tie is based on temperature anomaly in °C.

Natural climate patterns that persist for days, months, or even years can affect weather patterns around the world and impact the average global temperature. One such well-known global-scale pattern—the El Niño-Southern Oscillation (ENSO)—is a natural episodic fluctuation in sea surface temperature (El Niño) and the air pressure of the overlying atmosphere (Southern Oscillation) across the equatorial Pacific Ocean. Over a period of months to a few years, ENSO fluctuates between warmer-than-average ocean surface waters (El Niño) and cooler-than-average ocean surface waters (La Niña) in that region.

2012 ranked as the warmest "La Niña year", surpassing the previous record set in 2011. 2012 ranked as the third warmest "La Niña year", behind 2006 and 2009, which are currently tied for warmest. Two of the three warmest years on record (2010 and 1998) are "El Niño years". A La Niña (El Niño) year is defined here as occurring when the first three months of a calendar year meet the La Niña (El Niño) criteria as defined by the Climate Prediction Center. The globally-averaged temperature difference between 2010 (warmest year on record) and 2012 (10th warmest year) is 0.09°C (0.16°F).

Temperature anomalies color coded to show El Niño and La Niña years
Global Annual Temperature Anomalies

Separately, the average global land temperature was 0.90°C (1.62°F) above the 20th century average and ranked as the seventh warmest year on record. Because land surfaces generally have low heat capacity, temperature anomalies can vary greatly between months. Over the course of 2012, the average monthly land temperature anomaly ranged from +0.22°C (+0.40°F; December) to +1.39°C (+2.50°F; April), a difference of 1.17°C (2.10°F).

The ocean has a much higher heat capacity than land and thus anomalies tend to vary less over monthly timescales. During the year, the global monthly ocean temperature anomaly ranged from +0.30°C (+0.54°F; January) to +0.55°C (+0.99°F; September), a difference of 0.25°C (0.41°F). For the period January–December, a weakening La Niña during January–March and ensuing ENSO-neutral conditions for the rest of the year contributed to a globally-averaged ocean surface temperature anomaly of 0.45°C (0.81°F) above the 20th century average, tying with 2001 as the 10th warmest year on record. It was also the warmest global ocean temperature anomaly among all La Niña years. It was also tied with 2001 as the third warmest global ocean temperature anomaly among all La Niña years, behind 2006 and 2009. 2003 and 1998—both El Niño years—tie for the warmest years on record for ocean surface, at 0.52°C (0.94°F) above average.

January–December Anomaly Rank
(out of 133 years)
Records
°C °F Year(s) °C °F
Global
Land +0.90 ± 0.19 +1.62 ± 0.34 Warmest 7th 2007 +1.09 +1.96
Coolest 127th 1884, 1907 -0.59 -1.06
Ocean +0.45 ± 0.03 +0.81 ± 0.05 Warmest 10th 1998, 2003 +0.52 +0.94
Coolest 124th 1909, 1910 -0.45 -0.81
Ties: 2001
Land and Ocean +0.57 ± 0.08 +1.03 ± 0.14 Warmest 10th 2010 +0.66 +1.19
Coolest 124th 1911 -0.44 -0.79
Northern Hemisphere
Land +0.96 ± 0.24 +1.73 ± 0.43 Warmest 8th 2007 +1.22 +2.20
Coolest 126th 1884 -0.70 -1.26
Ocean +0.47 ± 0.04 +0.85 ± 0.07 Warmest 8th 2005 +0.55 +0.99
Coolest 126th 1910 -0.47 -0.85
Land and Ocean +0.65 ± 0.13 +1.17 ± 0.23 Warmest 8th 2010 +0.77 +1.39
Coolest 126th 1912 -0.47 -0.85
Ties: 2004
Southern Hemisphere
Land +0.76 ± 0.11 +1.37 ± 0.20 Warmest 5th 2005 +0.93 +1.67
Coolest 129th 1917 -0.62 -1.12
Ties: 2003
Ocean +0.45 ± 0.03 +0.81 ± 0.05 Warmest 11th 1998 +0.54 +0.97
Coolest 123rd 1911 -0.46 -0.83
Land and Ocean +0.50 ± 0.06 +0.90 ± 0.11 Warmest 9th 1998 +0.59 +1.06
Coolest 125th 1911 -0.46 -0.83
Ties: 1997

The 1901-2000 average combined land and ocean annual temperature is 13.9°C (56.9°F), the annually averaged land temperature for the same period is 8.5°C (47.3°F), and the long-term annually averaged sea surface temperature is 16.1°C (60.9°F).

Top Ten Global Weather/Climate Events for 2012

The following table list the top ten global weather/climate events of 2012. These events are listed according to their overall rank, as voted on by a panel of weather/climate experts. For additional information on these and other significant 2012 climate events, please visit NCDC's Top Ten Global Events webpage.

Rank Event When Occurred
1 Arctic Sea Ice Extent Late Spring Through Fall 2012
2 Agricultural Drought Summer 2012
3 Hurricane Sandy October 2012
4 Super Typhoon Bopha/Pablo December 2012
5 Northern Hemisphere Warmth Throughout 2012
6 Greenland Ice Sheet & Glacier Calving July 2012
7 Eurasian Continent Cold Wave January/February 2012
8 Northeastern Brazil Drought First Half of 2012
9 African Floods July - October 2012
10 Antarctic Sea Ice Extent September 2012

[ top ]


Regional Temperatures

Warmer-than-average temperatures occurred during 2012 for most of the world's surface. The greatest above-average annual temperature anomalies occurred across most of North and South America, central and southern Europe, much of northern and coastal Africa, and western, southern, and far northeastern Asia, with record warmth observed across much of central North America, central South America, parts of southern and eastern Europe, much of the northeastern coastal Atlantic Ocean, part of the southern Arctic Seas, and sections of the mid-latitude Southern oceans. Colder-than-average conditions occurred across most of Alaska, part of the northeastern and east central Pacific Ocean, and the Southern Ocean off the southern tip of South America.

A natural hemispheric-scale climate pattern called the Arctic Oscillation (AO) can be a dominating driver of winter temperatures in the Northern Hemisphere. Its effects were particularly felt from the end of January to mid-February, when the AO was negative. A negative AO is associated with cold polar air that spills southward into the mid-latitudes from the Arctic region and warm air that advects northward from nearer the equator.

Due at least in part to this pattern, frigid temperatures were felt across much of Europe during this time, bringing the worst cold snap to the region in at least the past 26 years. Hundreds of people perished across a dozen countries in central and eastern Europe due to the polar outbreak. Austria's average February temperature was the coldest on record for the month since 1986. Germany also experienced its coldest February since 1986 and 15th coldest since records began in 1881. Spain had its fourth coldest February since its records began in 1961. At the same time, part of Canada was much warmer than average, as temperatures in Ontario, Canada during February "rivaled record values set in 1998", according to Environment Canada. Temperatures across the region ranged from 3.7°C to 6.8°C (6.7°F to 12.2°F) above average. Overall, Canada observed its third warmest winter since national records began in 1948, with the average temperature 3.6°C (6.5°F) above average and virtually no parts of the country colder than average. And in contrast to the winters of 2009/10 and 2010/11, which were colder than average due to the impacts of the negative AO, the contiguous United States was not impacted in the same way by the climate pattern during this period, as it observed its fourth mildest winter since records began in 1895.

In the Southern Hemisphere, with La Niña still in place, Australia reported its 11th coolest average maximum and 15th coolest average minimum austral summer temperature in the country's 63-year period of record.

As winter gave way to spring in the Northern Hemisphere, warmer-than-average temperatures prevailed across much of this region. The contiguous United States had its warmest March on record. Norway also had its warmest March since national records began in 1900. Austria and Germany each had their third warmest March since records began in 1767 and 1881, respectively. The United Kingdom (UK) recorded its warmest March since 1957 and the third warmest since national records began in 1910. Provisionally, Scotland was record warm for the month.

The warmth continued in parts of North America in April, where the contiguous United States had its third warmest April on record. However, in Europe, the UK had its coolest average April temperature since 1989. According to the UK's Met Office, April 2012 was cooler than March 2012, an unusual event that last happened in 1998. It was also cooler than average in Spain, Norway, and Sweden during April.

In the Southern Hemisphere, the lingering effects of La Niña contributed to Australia's third lowest maximum March temperature and fourth lowest minimum autumn (March–May) temperature on record.

For the March–May period, the contiguous United States had its warmest spring on record and to the north, Canada had its ninth warmest such period. Across the Atlantic, Austria observed its seventh warmest spring in its 246-year period of record.

Austria's warmth carried over into June, as the country recorded its highest ever June temperature of 37.7°C (99.9°F) on the 30th in two locations—the capital city of Vienna and in German-Altenburg, Nope. The monthly temperature averaged across Austria was the sixth warmest June on record. However, in other parts of Europe, Norway had its 25th coolest June in its 113-year period of record and the UK had its coolest June since 1991. It was also the coolest July for the UK since 2000. In Australia, the average July maximum temperature was the lowest for that month in the past 30 years. It was a different story in North America, however, as the contiguous United States observed its hottest July (and hottest month ever) on record.

August brought warmer-than-average temperatures to many regions around the world. It was warmer-than-average across New Zealand and temperatures in Australia rebounded from July, with the average maximum temperature ranking as the sixth warmest on record for August. Two separate heat waves brought Spain its second warmest August since 1961, while Austria had its fourth warmest August on record.

The summer (June–August) period in Canada was 1.9°C (3.4°F) above the 1961–1990 average, making this Canada's all-time warmest summer in the 65-year period of record, beating the previous record set in 1998 by 0.2°C (0.4°F). A warmer-than-average August, combined with the record-high July temperatures and a warmer-than-average June brought the contiguous United States its second hottest summer on record.

Following the second warmest summer for Hungary since national records began in 1900, monthly temperatures remained above average across the entire country during September, ranging from about 1.0°–3.5°C (1.8°–6.3°F) above the 1971–2000 average.

Australia had its third warmest maximum September temperatures on record; and monthly-averaged daily, maximum, and minimum temperatures were all above average across Argentina, particularly in the central and northern regions of the country. These warm temperatures contributed to record September warmth across global land and ocean surfaces—the only globally-averaged record warm month of 2012.

A series of low pressure systems that plagued the UK during part of the year kept temperatures below average during October, with the lowest October temperature recorded since 2003. Scotland was the coolest since 1993. Meanwhile, central and southeastern Europe were warmer than average during the month. Temperatures were up to 1.6°C (2.9°F) above the 1961–1990 average across large parts of Croatia, while the Republic of Moldova reported monthly temperatures across the country that ranged from 2.5° to 3.5°C (4.5° to 6.3°F) above average.

November was cooler than average in New Zealand, while maximum temperatures were the fourth highest for November on record in Australia. In Europe, Hungary, Austria, Croatia, and the Republic of Moldova were warmer than average. However, in East Asia it was the fifth coolest October maximum temperature for South Korea. It was also colder than averge in China, with the national average temperature 0.9°C (1.6°F) below average. The regions of northern Xinjiang and central Inner Mongolia were 2°–4°C (4°–7°F) colder than average.

Beginning in late November, severe cold swept across much of Eurasia as the Arctic Oscillation became negative and remained strongly negative through December. This negative phase led the polar jet stream to dip down over Eurasia bringing frigid air from the north to the region to close out 2012. Northern and eastern China had its coldest period for this time of year in the past 28 years, according to China's National Climate Center. The capital city of Beijing observed its lowest average temperature since at least 1951. Through December, Russia experienced its coldest winter to date since 1938, with temperatures as much as 10°–15°C (18°–27°F) below average. Temperatures fell to as low as -50°C (-58°F) in some parts of Siberia. In Europe, the Republic of Moldova, Hungary, Sweden, Finland, and Norway were all colder than average during December. The U.S. state of Alaska observed its 18th coolest December since records began in 1918, with the average monthly temperature 3.3°C (5.9°F) below the 1971–2000 average. Conversely, Australia had its fourth highest December maximum temperatures since records began in 1910. And in New Zealand, many record or near-record monthly temperatures were reported across the North Island, around Nelson, and parts of the South Island.

Notably, for 2012 as a whole, the contiguous United States had its warmest year in its 118-year period of record, surpassing the previous record set in 1998 by 0.6°C (1.0°F). A list the top 10 weather and climate events for the United States is also available.

With winter, spring, and summer all among Canada's top 10 warmest for their respective seasons, the January–November period for 2012 was the fourth warmest since records began in 1948, according to Environment Canada. A list of Canada's top 10 weather and climate events of 2012 is also available.

In Europe, Austria experienced its seventh warmest year since national records began in 1767, at 1.0°C (1.8°F) above the long-term average. Norway had its 45th warmest year since records began in 1900, at 0.4°C (0.7°F) above average.

The 2012 temperature across the United Kingdom was 0.1°C (0.2°F) below the 1981–2010 average. This is in part attributed to the UK's coolest summer since 1998 and coolest autumn since 1993.

With the first half of 2012 cooler than average and the second half warmer than average, on balance the annual 2012 temperature across Australia was 0.06°C (0.11°F) above the 1961–1990 average. Only the year 2011 has been below average in the past decade.

[ top ]


Global Precipitation

Following the two wettest years on record (2010 and 2011), 2012 saw near average precipitation on balance for land areas across the globe. Precipitation anomalies were variable from region to region.

La Niña conditions brought heavy rainfall to Australia, especially in the east, during the first few months of 2012, but conditions turned drier during the latter half of the year after ENSO-neutral conditions took hold. From April through December, rainfall was generally below average for the period. According to the Bureau of Meteorology, a positive Indian Ocean dipole, associated with cooler sea surface temperatures off the northwest coast of Australia and typically drier conditions across parts of the continent, emerged in early August and continued into October. This likely contributed to drier-than-average conditions across southern Australia. Overall, following the record wet year of 2011, 2012 precipitation was near the median of annual values dating back to 1900.

The year started off rather dry for the United Kingdom and then changed fairly abruptly. Following its driest March on record, the UK observed its all-time wettest April. A series of low pressure systems continued to impact the country, with June also being record wet. Remarkably, even with the dry conditions early on, the UK had its second wettest year since records began in 1910, falling just 7.3 mm (0.29 inches) shy of the record wetness of 2000. Provisionally, England had its all-time wettest year on record.

Finland was wetter than average for 2012, with many stations observing their wettest year in the past half century. The capital city of Helsinki reported its second wettest year, behind 1944, since records began in the early 19th century.

In northern Brazil, lack of rain during first half of 2012 led to the worst drought in five decades and resulted in "water wars" which provoked extreme behavior and led to fatalities. An estimated 4 million people were affected. Water supplies were threatened in 1,100 municipalities. Some regions in northeastern Brazil had their record driest January–October on record, according to the World Meteorological Organization (WMO).

In the contiguous United States, in addition to the summer being hot for a large part of the country, it was also dry, resulting in a drought footprint comparable to the drought episodes of the 1950s. The drought peaked in July, when the percent area of the CONUS in at least moderate drought was 61.8 percent, according to the Palmer Drought Severity Index (PDSI). The summer was the 14th driest on record for the country. The epicenter of the drought stretched from the Rockies through the Great Plains and into the Midwest. The drought resulted in a multi-billion dollar agricultural disaster—the most severe and extensive drought impact since 1988.

At the same time, drought gripped western Russia, western Siberia, Ukraine, and Kazakhstan, damaging agricultural crops. According to the WMO, more than $630 million U.S. dollars in damages were incurred in western Russia and western Siberia alone.

Several countries in eastern Europe, including Romania, Hungary, Bulgaria, and Poland, experienced drought during September. It was one of worst droughts for Hungary in two decades.

It was also extremely wet in some areas of the world. According to the Japan Meteorological Agency, record 24-hour rainfall of up to 500 mm (20 inches) was observed on Japan's southern island of Kyushu in mid-July. Subsequent flooding and landslides killed more than two dozen residents. In and around Beijing, China, up to 170 mm (6.7 inches) of rain fell within a 16-hour period on July 21st, leading to the worst flooding in six decades in the region.

The South Asian monsoon season in India starts around the beginning of June and lasts into October. Rainfall during the pre-monsoon season was the lowest on record since 1901 and rainfall continued to be deficient during the first half of the monsoon season. However, the monsoon stalled over northwestern India before beginning its annual withdrawal, bringing excessive rainfall to most of the region during the month of September. The heavy rainfall brought seasonal precipitation totals to within the normal range and alleviated drought conditions for much, but not all, of the country. By the withdrawal date on October 10th, India as a whole experienced rainfall that was 92 percent of average, within the normal range, according to the India Meteorological Department.

During mid-September, Super Typhoon Sanba—the year's first category 5 storm among all tropical cyclone basins—brought locally heavy rainfall to Okinawa Island, Japan, parts of the Philippines, including the capital city of Manilla, and both North and South Korea. Super Typhoon Jelawat—the year's second category 5 storm—also impacted part of the eastern Philippines and parts of Japan, including Okinawa and Tokyo.

At the end of September, Sandy dumped copious rain over Jamaica, Haiti, the Dominican Republic, Cuba, and much of the eastern United States. Post-tropical storm Sandy also brought blizzard conditions to the Central and Southern Appalachians, shattering all-time U.S. October monthly and single storm snowfall records.

The rainy season was wetter-than-normal across western and central Africa. From July to October, over 3 million people were affected across 15 countries, most notably in Nigeria, Niger, Senegal, and Chad.

Tropical cyclones rarely hit the southern Philippines; however, Category 5 Super Typhoon Bopha struck southern Mindanao Island in early December, dumping copious rainfall over the region, killing more than 900 residents, and leaving more than 600 missing. This is the same region where Tropical Storm Washi hit just one year earlier, in December 2011, killing more than 1300 people.

[ top ]


References

Peterson, T.C. and R.S. Vose, 1997: An Overview of the Global Historical Climatology Network Database. Bull. Amer. Meteorol. Soc., 78, 2837-2849.

Quayle, R.G., T.C. Peterson, A.N. Basist, and C. S. Godfrey, 1999: An operational near-real-time global temperature index. Geophys. Res. Lett., 26, 333-335.

Smith, T.M., and R.W. Reynolds (2005), A global merged land air and sea surface temperature reconstruction based on historical observations (1880-1997), J. Clim., 18, 2021-2036.

Smith, et al (2008), Improvements to NOAA's Historical Merged Land-Ocean Surface Temperature Analysis (1880-2006), J. Climate., 21, 2283-2293.

[ top ]

National Snow & Ice

NCDC transitioned to the nClimDiv dataset on Thursday, March 13, 2014. This was coincident with the release of the February 2014 monthly monitoring report. For details on this transition, please visit our public FTP site and our U.S. Climate Divisional Database site.


The 2011/12 winter season was nearly non-existent for much of the eastern half of the nation. The December 2011-February 2012 three-month period was marked by near-record warmth across the U.S.-Canadian border, the Midwest, Mid-Atlantic, and Northeast, limiting seasonal snowfall across those regions. Many locations had near-record low snowfall totals for the winter season. Early spring brought much of the same, when the contiguous U.S. had its warmest March on record, with a monthly temperature 8.6°F above average. The lack of snowfall and snowpack for the winter and spring across the Rockies, Great Plains, and Midwest was a precursor to the large drought episode that impacted two-thirds of the nation during the summer and autumn of 2012. In contrast to the rest of the nation, the Pacific Northwest was closer to average during winter in terms of temperature and precipitation, with several winter storms bringing heavy snowfall to the high elevations. The early-spring was wetter and cooler than average for the Northwest, contributing to above-average snowfall for many locations in the region.

US Winter snow extent anomalies
Contiguous U.S. Winter Snow Cover Extent Anomalies
Data Source: Rutgers Global Snow Lab

According to data from the Rutgers Global Snow Lab, both the winter and spring seasons brought below-average snow cover to the contiguous United States. The satellite-derived snow cover extent for December 2011-February 2012 was approximately 237,000 square miles below the 1981-2010 average — the third smallest winter snow cover footprint in the 46-year satellite record. This was the first winter since 2005-2006 with below-average snow cover for the country. Only the winter seasons of 1991/92 and 1980/81 had smaller snow cover extents. The March-May spring snow cover extent was 151,000 square miles below the 1981-2010 average — the third smallest spring snow cover extent on record. The springs of 1968 and 2000 had smaller seasonal snow cover footprints.

Western US Snowpack 1 May 2012
Western U.S. Snowpack
April 1, 2012
Source: USDA

Winter and spring mountain snowpack provide a crucial water source across much of the western United States. The total annual water budget for agriculture and human use in the mountainous West is highly dependant on the amount of snow melt that will occur in spring and is proportional to the amount of snow on the ground. The annual snowpack typically reaches its maximum value at the end of March. According to data from the USDA, on April 1st, 2012, above-normal snowpack was observed through the Cascades of Oregon and Washington, with near-normal snowpack stretching eastward through the northern Rockies of Idaho, Montana, and northern Wyoming. To the south, below and much-below snowpack was observed for the Sierra Nevada Mountains, the Great Basin, and the Central and Southern Rockies. Snowpack totals less than 50 percent of normal were widespread in California, Nevada, Utah, Colorado, Arizona, and New Mexico. In Alaska, snowpack totals were above normal for the Southern coasts and peninsula, and below-normal across the North Slope.

Select Significant Events

A strong and powerful winter storm moved across the Southern Rockies and High Plains of Colorado, New Mexico, Texas, Oklahoma, and Kansas on December 19th and 20th of 2011. Snowfall up to 15 inches was reported across the region, and strong winds in excess of 50 mph created blizzard conditions. Parts of Interstates 25 and 70 were closed, and the storm was blamed for six deaths. Dalhart, Texas, shattered its daily snowfall record, where 7.0 inches fell on the 19th, surpassing the 0.1 inch which fell on the date in 1983. The 8.2 inches that accumulated in Pueblo, Colorado during the two-day event contributed to the city having its snowiest December on record, with 18.6 inches falling throughout the month. This surpassed the previous December record of 18.2 inches, which fell in December 1913.

Satellite Image of December 19-20 Snow Cover
Satellite Image of Pacific Northwest Snowcover
Source: NASA

A large and powerful winter storm, accompanied by a surge of moisture from the tropics often referred to as an atmospheric river or the 'Pineapple Express', impacted the western U.S. January 18th–23rd. The worst impacts were felt across the Pacific Northwest, where several feet of snow accumulated and strong winds were observed, causing icy roads, downed power lines, and avalanches. A state of emergency was declared for much of Oregon and Washington, where over a quarter-million households lost electricity. Impressive wind, snow, and rain measurements were made during the event Mount Hood, Oregon received over 50 inches of snow, winds approaching 90 mph were measured at Summer Lake, Oregon, and over 15 inches of rain fell at Swiss Home, Oregon. The Mary’s River in Philomath, Oregon crested at its highest flood height on record. Seven inches of snow fell in Seattle, which averages only 8 inches of snow a year. To the south, across the high terrain of California and Nevada, the precipitation was a welcome sight, where very dry conditions had previously dominated during the 2011-2012 winter season. Nevada’s Carson River Basin had snowpack only 8 percent of normal before the storm (compared to 224 percent at the same point in January 2011, one year prior).

A record-breaking snow storm impacted eastern Colorado and parts of Nebraska February 2nd–4th. The slow moving storm dropped 15.9 inches of snow in Denver, a new February snow storm record, surpassing the previous record of 14.1 inches set in February 1912. The 22.7 inches that fell in Boulder was also a February record. Snow accumulations greater than three feet were widespread across the region's highest terrain. Storms of this magnitude are more common in the region during the early spring months of March and April. As the storm moved off to the east it dropped upwards of a foot of snow across much of Nebraska. The 11.1 inches that accumulated in Lincoln, Nebraska was the fourth largest 24-hour snowfall on record for the city.

Snow totals Feb 29 2012
Satellite Image of CO and NE Snow Cover
Source: NWS

A potent storm system on February 28th and 29th brought heavy snowfall and blizzard conditions across the Northern Plains, Great Lakes, and into the Northeast. Snowfall totals exceeding one foot fell in a string of states from South Dakota to Maine. The heaviest snow fell across Minnesota and Wisconsin, where snow totals approached two feet, accompanied by winds gusting to 50 mph, creating blizzard conditions for several hours. The snow from this storm was one of the few snow events this season across many of the regions affected. Much of the Northern Plains, Great Lakes

Pacific NW March 22 snowfall
22 March Pacific Northwest Snowfall
Source: National Snow Analysis

During March, as much of the eastern U.S. was basking in record breaking warmth, an upper-level trough brought cooler-than-average conditions and late-season precipitation to the Pacific Northwest. On March 22nd, a large Pacific extra-tropical cyclone slammed into the West Coast, dumping upwards of three feet of snow across the high elevations of the Washington and Oregon Cascade Mountains. The 0.5 inch of snow that fell at the Portland, Oregon airport was the largest snowfall accumulation this late in the season. Salem and Eugene, Oregon both set new March snow storm records with 2.5 and 7.5 inches of snow, respectively. This storm was part of a larger and persistent weather pattern which brought much-above-average precipitation and below-average temperatures to the region during March. The 7.89 inches of precipitation that accumulated in Portland was a new monthly record.

April 24th Northeast Snow Depth
24 April Northeast Snow Depth
Source: NOAA NNVL

A late-season storm dropped over a foot of snow from West Virginia to Upstate New York, along the higher elevations of central and northern Appalachian Mountains, on April 23rd and 24th. To the east, in the lower elevations, heavy rain fell across the large cities of the Northeast. This type of coastal storm, called a Nor’easter, was only the second of the season to impact the eastern seaboard, with the other being very early in the season in October. The snow storm was also on the heels of the warmest March on record for many locations across the region, where most trees already had begun to leaf. The snow falling on trees with leaves caused additional headaches by bringing down limbs and cutting power to at least 75,000 residents. The storm also resulted in at least 48 daily snowfall records. Although the storm did have some negative impacts, it provided drought-relieving precipitation for many locations in the Northeast.

Sandy Snowfall Totals
Sandy remnant-low snowfall totals

The remnant low pressure system from Hurricane Sandy dropped copious amounts of snow across the Southern and Central Appalachians as it moved westward after making landfall near Atlantic City, New Jersey on October 29th. Over a foot of snow was reported in six states from North Carolina to Pennsylvania, shattering October monthly snowfall records. Widespread, heavy snow of this magnitude during October has never been observed across this region. The largest snow totals occurred along the highest elevations of the Appalachians, with Mount Leconte, Tennessee receiving 33 inches of snow and Terra Alta, West Virginia measuring 36 inches. Very strong winds combined with the snow to create blizzard conditions for up to two days in some locations. The largest impacts of the storm were the massive power outages due to downed trees and power lines and building collapses because of the heavy, wet nature of the snow. Flooding was also a concern as warm temperatures returned quickly after the storm causing rapid melt and runoff.

Tornadoes

NCDC transitioned to the nClimDiv dataset on Thursday, March 13, 2014. This was coincident with the release of the February 2014 monthly monitoring report. For details on this transition, please visit our public FTP site and our U.S. Climate Divisional Database site.

Issued: 8 January 2013

On the heels of one of the most destructive tornado years on record for the country (2011), tornado activity during 2012 was below average. During 2012, there were 878 confirmed tornadoes during January–October, with 58 tornado reports still pending for November and December according to data form the Storm Prediction Center. The 1991-2010 annual tornado average is 1,253 and 2012 marks the slowest tornado year since 2002 when there were 934 tornadoes. If the confirmed tornado count is below 935, depending on the confirmation rate of the end-of-year tornadoes, 2012 could be the slowest tornado year since 1989 which had 856 tornadoes. Despite the slower-than-average year for tornadoes, there were still several large, destructive, and deadly tornado outbreaks during the year. Three tornado outbreaks caused at least one billion dollars in damage and there were 68 tornado-related fatalities.

The last tornado-related fatality in the U.S. occurred on June 24th, so December 31st was the 190th consecutive day without a tornado-related fatality. According to analysis by the Storm Prediction Center, the longest consecutive day stretch with no tornado fatalities in the 1950-present official record was 197 days between August 15th 1986 and February 28th 1987. Longer periods without tornado fatalities have occurred prior to 1950, but inconsistent observing practices make comparisons to current data difficult.

The 2012 tornado year started off above average, with above-average tornado activity for each month between January and April. The lack of storm systems during the late spring and summer across the Great Plains was associated with a lack of tornadoes. May and June, which are typically the most active months of the year, both had less than 50 percent of average number of tornadoes confirmed. The below-average tornado activity continued through November. The most active regions of the country during 2012 were the Central Plains, the Gulf Coast, and the Ohio Valley. An active storm pattern during December along the Gulf Coast caused the monthly tornado count to be above average, according to preliminary data. The tornadoes that did form during 2012 tended to be weak to moderate strength in nature. There were only four EF-4 tornadoes, the least since 2009, with no confirmed EF-5 tornadoes during the year.

Significant Events

An early-season tornado outbreak hit the Ohio Valley and Southeast on March 2nd and 3rd. Seventy-five tornadoes were confirmed in 12 states from Illinois to Florida. It was early in the tornado-season for an outbreak of this magnitude and was one of the largest tornado outbreaks on record during March. The tornado outbreak was spawned as a large low-pressure system moved through the mid-Mississippi River Valley into the Ohio Valley. Ahead of the associated cold front, temperatures surged into the 70s and 80s (degrees F), which is more than 20 °F above average. This was the deadliest tornado outbreak during 2012 with 40 fatalities. The 11 deaths associated with the EF-4 tornado which moved through four counties in southern Indiana was the deadliest single tornado of 2012. An EF-3 tornado in eastern Kentucky and western West Virginia was on the ground for 85 miles and caused 10 fatalities, marking the longest tracked tornado of the year. Damage from the event was expected to exceed one billion U.S. dollars.

On March 9th, a cut-off low pressure system impacted the Hawaiian Islands, bringing heavy rainfall and severe thunderstorms to the windward portions of the archipelago. A waterspout (a tornado over water) made landfall on Oahu hitting the towns of Lanikai and Kailua. The tornado caused some minor damage and was rated an EF-0. Tornadoes are rare in Hawaii, with only seven confirmed tornadoes impacting the state since 1950. The same system produced a severe thunderstorm which dropped a hailstone on Oahu measuring 4.25 inches long, 2.25 inches tall, and 2 inches wide, breaking the record for largest hail stone measured in Hawaii. The previous state record hailstone was 1 inch in diameter.

On March 15th, an amplified weather pattern, more typical of summer, allowed warm and moist conditions to surge northward into Michigan. An upper-level low pressure system moving into the unstable environment set off several thunderstorms across the region. One of the tornadoes, near Dexter, Michigan, was rated an EF-3 with winds of 135-140 mph. The tornado marked the earliest EF-3 to impact the state in the 1950-present modern record. The tornado had a 7.2 mile path length, with a maximum width of 800 yards, destroying nearly 130 buildings in its path. There were no reported fatalities or injuries with the storm.

On April 3rd, a series of supercell thunderstorms moved through the Dallas-Fort Worth Metroplex, spawning 22 tornadoes in the densely populated area. Most of the tornadoes were weak and rated EF-0 and EF-1, while three were rated EF-2 and two were rated EF-3. The Dallas-Fort Worth International Airport, one of the busiest in the nation, halted all flights and sheltered all passengers as a precaution due to the tornado warnings. The tornadoes caused significant damage across Dallas-Fort Worth, but they did miss the airport and there were no reported fatalities for the entire outbreak. Damage from the event was expected to exceed one billion U.S. dollars.

A tornado outbreak on April 14th and 15th spawned 98 tornadoes across the Central Plains and Southern Plains, causing 6 fatalities. This outbreak was the largest during 2012 and helped push the monthly U.S. tornado count to 206. The monthly tornado count was higher than both May and June, the two typically most active tornado months of the year. This was only the third time since 1980 this has occurred. The tornadoes were spawned as a vigorous storm system moved through the region. An EF-3 tornado moved through the town of Woodward, Oklahoma causing the six fatalities. Damage from the event was expected to exceed one billion U.S. dollars.

[ top ]

Hurricanes & Tropical Storms

NCDC transitioned to the nClimDiv dataset on Thursday, March 13, 2014. This was coincident with the release of the February 2014 monthly monitoring report. For details on this transition, please visit our public FTP site and our U.S. Climate Divisional Database site.


Atlantic Basin

2012 Season Summary:

The 2012 North Atlantic hurricane season had 19 named storms, ten hurricanes, and one major hurricane. The number of named storms marked the third consecutive hurricane season with 19 named storms for the basin and tied with 2011, 2010, 1995, and 1887 as the third busiest year for North Atlantic tropical cyclones. An average season has 11 named storms, six hurricanes, and two major hurricanes (Category 3 strength or stronger). The number of named storms and storms that reached hurricane strength was above average, while the number of major hurricanes was below average. The 2012 season marked the lowest number of major hurricanes in the basin since 1997, which also had only one. There were no Category 4 or 5 storms during the season, only the third time this has occurred since 1995. Hurricane Michael, the only Category 3 hurricane of the season, retained major hurricane strength for 6 hours. One hurricane (Isaac), two tropical storms (Beryl and Debby), and one post-tropical storm with hurricane force winds (Sandy) made landfall during the season. No major hurricanes struck the U.S. coast, marking the seventh consecutive year without a major hurricane strike.

The Accumulated Cyclone Energy (ACE) index of tropical cyclone activity also indicated an above-average season. The ACE index is used to calculated the intensity of the hurricane season and is a function of the wind speed of each tropical cyclone. The 2012 Atlantic hurricane season had an approximate ACE value of 128 (x104 knots2) which was above the 1981-2010 median value of 93 (x104 knots2) and nearly the same value as the 2011 season. The highest ACE index on record occurred during the 2005 season, which had an ACE index of 250 (x104 knots2). Although there was an extremely high number of tropical storms during the year, the below-average number of major hurricanes kept the seasonal ACE value relatively low compared to more active years.

The above-average season was associated with much warmer-than-average sea surface temperatures across a large area of the North Atlantic, and an active African easterly jet that generated numerous tropical waves which developed into tropical storms. Above-average wind shear and atmospheric stability inhibited the tropical storms that did develop from becoming major hurricanes.

Several aspects of the 2012 North Atlantic hurricane season were unique. Tropical Storm Beryl, which formed on May 25th and made landfall near Jacksonville, Florida, on May 28th, was only the third time on record that the second named storm of the year formed before June 1st (the official start of the hurricane season). Beryl was also the strongest tropical storm to make landfall in the U.S. during the month of May. Tropical Storm Debby’s formation on June 23rd was the first time there have been four named storms in the basin before July 1st. Hurricane Nadine, which formed on September 12th and dissipated on October 4th was the fifth longest-lived tropical cyclone on record for the North Atlantic. Post-tropical cyclone Sandy, which made landfall near Atlantic City, New Jersey, in October, will likely be the second costliest storm system to impact the United States, behind Hurricane Katrina.

Individual tropical cyclone summaries are available through NOAA's National Hurricane Center.


East Pacific Basin

2012 Season Summary:

The Eastern Pacific Basin experienced slightly above-average tropical cyclone activity during 2012. The basin had 17 named storms, 10 hurricanes, and five major hurricanes. On average the basin experiences 15 named storms, nine hurricanes, and four major hurricanes. The ACE value of 98 (x104 knots2) was slightly below the 1981-2010 median of 100 (x104 knots2) and marked a near-normal season for the basin. During the entire season, ENSO-neutral conditions (neither El Niño nor La Niña) were present across the Equatorial Pacific, which favors a near-average hurricane season for the basin. Hurricanes Carlotta and Paul caused significant damage in Mexico, while six additional storms threatened land but had minimal impacts.

Hurricane Bud formed early in the season, reaching Category 3 strength on May 24th with sustained winds of 115 mph and a minimum central pressure of 961 mb — the earliest date for a storm of this strength on record for the Eastern Pacific Basin. During the subsequent days, Bud quickly weakened and by the 26th was only a remnant low. The remnants of the storm caused minimal damage along Mexico’s Pacific coast.

Hurricane Carlotta developed on June 13th and reached tropical storm strength by the 14th as it moved over warm waters with low wind shear in the atmosphere. On the 15th Carlotta strengthened into a Category 2 hurricane with winds of 105 mph. Carlotta made landfall near Puerto Escondido, Mexico, on the 16th after weakening to a Category 1 hurricane with winds of 90 mph. The storm caused over $100 million U.S. dollars worth of damage and led to at least 7 fatalities.

Hurricane Paul formed from a trough of low pressure in mid-October reaching tropical storm strength on October 13th. Warm water, low shear, and high relative humidity caused Paul to rapidly intensify into a hurricane on the 15th. Paul reached maximum strength late in the day on the 15th with sustained winds of 120 mph, marking the fifth major hurricane of the 2012 season. Paul’s strength waned on the 16th, and weakened to a tropical storm and eventually a tropical depression on the 17th. Paul brushed the coast of Baja California Sur, causing damage in La Paz. There were no reported fatalities from the storm, and damage was estimated at $15.5 million U.S. dollars.

Individual tropical cyclone summaries are available through NOAA's National Hurricane Center.

[ top ]

Drought

NCDC transitioned to the nClimDiv dataset on Thursday, March 13, 2014. This was coincident with the release of the February 2014 monthly monitoring report. For details on this transition, please visit our public FTP site and our U.S. Climate Divisional Database site.

Issued 8 January 2013
The data presented in this drought report are preliminary. Ranks, anomalies, and percent areas may change as more complete data are received and processed.
Contents Of This Report:
Graph showing National Palmer Z Index

National Drought Overview

graph showing percent area of the contiguous U.S. very wet and very dry for January-December 2012

On a month-by-month basis, 2012 was characterized by large areas of dry and, earlier in the year, large areas of wet weather. Eight months (all except January, February, October, and December) had ten percent or more of the country experiencing very dry (at the tenth percentile of the historical record or drier) precipitation anomalies, with five months (May, June, August, September, and November) having more than a fifth (20 percent) of the country very dry. June and November had a third of the country very dry. The percent area very wet (monthly precipitation totals at the 90th percentile of the historical record or wetter) stayed under ten percent for all but one of the months in the year, with March having the largest percent area very wet (16%). When averaged together, the wet and dry anomalies resulted in the 20th driest February, 23rd driest May, 10th driest June, 22nd driest July, and 8th driest November, nationally, in the 1895-2012 record. Large areas of the country also experienced unusually warm conditions. Ten percent or more of the contiguous U.S. was very warm (monthly temperatures at the 90th percentile of the historical record or warmer) during every month except October. More than a fourth (25%) was very warm during eight months, with July (60%) and March (75%) having more than half of the country very warm. This persistent and anomalous heat resulted in the warmest month ever (July 2012), ranked 2012 as the warmest year on record, and (especially during the growing season) increased evaporation and intensified local drought conditions.

An important feature of the weather conditions in 2012 was the persistence of the areas of dryness and warm temperatures, the magnitude of the extremes, and the large area they encompassed. Dry weather affected parts of the West almost every month, especially the Intermountain Basin during April-July, the Southwest during April-June and October-November, and the Rockies during March-November. The Central Great Plains were plagued by dryness much of the year (especially March-November), with dryness especially acute during the summer across the Plains (June-August). Dry weather dominated across the Central Plains to Midwest agricultural areas during the critical May-July growing season, but the dryness lasted longer in parts of this region (for example, the Midwest during February-July). August-September saw very dry weather from the Pacific Northwest, across the Northern Rockies and Central to Northern Plains, and into the western Great Lakes. Dry weather afflicted the eastern U.S. early in the year, with the Southeast dry during January-April and the Northeast during February-April. Large areas of the country were very dry during May-June (from the West Coast to the Ohio and Tennessee valleys), August-September (from the Pacific Northwest to the western Great Lakes), and November (from the Southwest and Southern Plains to the Northeast and Southeast).

2012
Standardized
Precipitation
Index maps:
2012
Standardized
Temperature
Index maps:
2012
Palmer Z
Index
maps:

The hot temperatures exacerbated the impact of the dry weather. When maps of the dryness (Standardized Precipitation Index [SPI]) are compared to maps of the Palmer Z Index (which incorporates the effects of both dryness and heat), larger areas of monthly drought are evident on the Z Index maps for March (SPI, Z Index), April (SPI, Z Index), May (SPI, Z Index), July (SPI, Z Index), and November (SPI, Z Index).



2012
U.S. Drought
Monitor maps:
2012
Palmer Drought
Severity Index maps:

The year started out with 31.9 percent of the contiguous U.S. in moderate to exceptional drought (based on the U.S. Drought Monitor [USDM]) manifested in two drought epicenters — areas of moderate to exceptional drought in the Southern Plains and moderate to extreme drought in the Southeast — with areas of moderate to severe drought in the Upper Mississippi Valley and moderate drought in the Far West. As the year progressed, the western drought expanded to link with the Southern Plains drought area and new drought areas developed along the East Coast, pushing the national drought area to 38.2 percent by May 1. Dryness during the late spring began to take its toll in the agricultural heartland by summer as drought intensified and expanded to cover much of the country from the Central Rockies to the Ohio Valley, and the Mexican border to the Canadian border, by the end of August. This solid mass of drought, which stretched from border to border and (by now) West Coast to Mississippi River, persisted through the fall. The percentage area in drought peaked at about 65.5 percent on September 25 (a new high in the 1999-2012 USDM record) and ended the year at 61.1 percent. The percent area of the contiguous U.S. in the worst drought categories (D3-D4, extreme to exceptional drought) peaked at 24.1 percent on August 7, which is also a record.

Percent of US Area in Moderate to Exceptional Drought since 2000 (based on USDM)

The percent area* of the contiguous U.S. experiencing moderate to extreme drought (based on the Palmer Drought Index) started the year at about 22.9 percent, grew steadily to a peak of about 61.8 percent during the summer, then contracted slightly during the fall, ending the year at about 51.8 percent. The Palmer Drought Index data go back 113 years.

Percent of US Area in Moderate to Extreme Drought since 1900 Percent of US Area in Moderate to Extreme Drought since 1996

*This drought statistic is based on the Palmer Drought Index, a widely used measure of drought. The Palmer Drought Index uses numerical values derived from weather and climate data to classify moisture conditions throughout the contiguous United States and includes drought categories on a scale from mild to moderate, severe and extreme.

[top]


Regional Drought Overview

map showing U.S. Drought Monitor for August 28, 2012

The year began with drought epicenters in the Southern Plains, Southeast, Upper Midwest, Far West, and Hawaii. As winter ended and spring began, dryness in the West spread to join the Plains and West drought areas while the Southeast drought crept up the East Coast. The spring months were quite dry with drought spreading or pockets of drought developing in several regions. The summer months were extremely dry across a large part of the central U.S., with the result being a merging of the drought epicenters in the West, Plains, and Midwest into one large drought area stretching from the West Coast to the Great Lakes. Beneficial autumn rains helped portions of the Midwest recover from drought, but dryness continued in the Plains where drought intensified. By the end of 2012, three drought epicenters remained — Hawaii, the Southeast, and one large area of drought stretching from the southern California coast across the West and Great Plains to the Midwest, with the worst drought conditions focused on the Plains states.

The dry weather (which lowered moisture supplies), coupled with intense spring and summer heat (which increased evapotranspiration and, thus, moisture demand), depleted soil moisture, lowered streamflow (May, June, July, August), reservoir and stock pond levels, and ravaged crops and livestock. By year's end, low river levels threatened commerce on the vital Mississippi River shipping lanes.

West:

Percent area of the West in moderate to exceptional drought, 2000-2012, based on the USDM
The percent area of the West in moderate to exceptional drought steadily grew during 2012, peaking at 77% in October.

The West began the hydrologic year (water year, October-September) on a dry note, with below-normal precipitation and snowpack water content. As the wet season (October-April) ended, the southern portions of the West had significant precipitation and snow water content deficits, while the northern areas were not as bad off. Continued dryness and intense heat during the spring and summer caused numerous wildfires to break out, with Colorado especially hard hit. Record heat and near-record dryness occurred in the state, with April-June 2012 ranking as the hottest and third driest April-June on record. Wyoming was record dry for several time scales, including June-August, April-August, March-August, June-September, May-September, April-September, and several others. Utah was record dry in June and April-June. A total of four states (Colorado, Nevada, Utah, Wyoming) ranked in the top ten driest category for April-June, six states were in the top ten driest for January-June, and three for January-November, including Colorado and Wyoming (which were record dry) and New Mexico (second driest). The weather pattern shifted during summer and early autumn, bringing much-needed precipitation to the southern areas but drying out the northern states. Five western states (Idaho, Montana, Oregon, Washington, Wyoming) ranked in the top ten driest category for July-September, with Montana having the driest August-September and July-September on record. When last year's dryness is combined with this year's dryness, the last two years (December 2010-November 2012) in New Mexico ranked as the driest such 24-month period on record. For January-December 2012, three states (Wyoming [driest], New Mexico [second driest], Colorado [fourth driest]) ranked in the top ten driest category and three other states (Arizona, Montana, Utah) ranked in the driest third of the historical record.

Percent area of the West in moderate to extreme drought, 1900-2012, based on the Palmer Drought Index

The percent area of the West in moderate to exceptional drought, as measured by the USDM, steadily grew during 2012, peaking at about 77.2 percent in October. Based on the Palmer Drought Index, which goes back to the beginning of the 20th century, moderate to extreme drought peaked at about 67.2 percent of the West during June. Both of these numbers were surpassed by the 2002-2003 drought and (for the Palmer index) earlier droughts.

Map of state precipitation ranks for January-December 2012 Colorado statewide temperature, April-June, 1895-2012

Wyoming statewide precipitation, January-December, 1895-2012 Colorado statewide PHDI, January 1900-December 2012


Great Plains and Midwest:

Percent area of the High Plains in moderate to exceptional drought, 2000-2012, based on the USDM
The percent area of the High Plains (Kansas to North Dakota) in moderate to exceptional drought skyrocketed during summer 2012, covering nearly the entire High Plains region by October.

Last year, drought was centered in the Southern Plains. This year, the entire Plains region was afflicted by drought with a significant part of the Midwest sharing the misery. Dryness affected the Northern Plains during March, the Southern Plains during April, and the Southern to Central Plains during May, with different portions of the Midwest affected during each of those months. But that was just a prelude to even worse conditions. The entire Plains and Midwest were baked and moisture-starved during June and July. Beneficial rains came to parts of the Midwest and Southern Plains during August and September, and to the Northern Plains and Midwest in October, but widespread dry conditions returned in November.

Record dryness occurred for several states in August and September. The persistence of drought gave several states record dry seasons, including Arkansas (April-June and other seasons), Kansas (May-July), Nebraska (June-August and other seasons), and South Dakota (July-September). Six states in the Plains and Midwest (Arkansas, Indiana, Iowa, Kansas, Missouri, Nebraska) ranked in the top ten driest category for January-November, with Nebraska having the driest January-November on record. For January-December 2012, five Great Plains and Midwest states ranked in the top ten driest category, including Nebraska which had the driest year on record.

The percent area of the Great Plains and Midwest in moderate to exceptional drought, as measured and defined by the USDM regions, rapidly increased during 2012. Nearly all of the Northern Plains was enveloped in drought by October, which is a record in the 13-year USDM history. Drought coverage also rapidly increased in the Midwest, peaking at about 73.7 percent in July, which is also a USDM record. In early 2012, the Southern Plains was recovering from the 2011 drought. The percent area in moderate to exceptional drought decreased to a low of about 32.3 percent in May 2012 before expanding again to peak at about 73.7 percent in July.

6-month SPI map for March-August 2012 West North Central Region temperature, March-August, 1895-2012

Nebraska statewide precipitation, January-December, 1895-2012 Palmer Hydrological Drought Index for Nebraska, January 1900-December 2012

Southeast to Northeast:

Percent area of the Southeast in moderate to exceptional drought, 2000-2012, based on the USDM
The percent area of the Southeast in moderate to exceptional drought oscillated up and down during 2012.

The precipitation pattern for the eastern U.S. fluctuated between wet and dry during 2012. The Southeast started the year on the dry side, with January-February ranking in the driest third of the historical record for several states. February-April was dry for the Northeast, with Connecticut having the driest February-April on record and most other states ranking in the top ten driest category. Three southeastern states (Alabama, Georgia, and Tennessee) ranked in the top ten driest category for April. The weather patterns, which brought drought to the Great Plains and Midwest during the late spring and summer, doused many of the eastern states with beneficial rainfall during this time. Although helpful, the rains were not enough to erase several years' of deficits in the Southeast. November was dry for all eastern states, with most ranking in the top ten driest category. The cumulative impact of the 2012 precipitation deficits gave Delaware the fourth driest January-November and Georgia, the epicenter of the Southeast drought, the eighth driest January-November. For the year (January-December), several states along the eastern seaboard were drier than normal, with Georgia ranking tenth driest and Delaware having the sixth driest year on record. The prolonged dryness in parts of the Southeast gave Georgia the driest December-November 24-month period (December 2010-November 2012) on record.

Parts of the Southeast have been in drought for the last two years. The percent area of the Southeast in moderate to exceptional drought, as measured by the USDM, hovered around 50 to 65 percent during the first five months of the year, then contracted during the summer and fall before expanding again at the end of the year. It peaked at about 69 percent at the beginning of May.

Georgia Statewide Precipitation, 24-month periods December-November, 1895-2012 Georgia Statewide Palmer Hydrological Drought Index, January 1900-December 2012





Hawaii and other Pacific Islands:

Kahului, Hawaii, precipitation, January-December, 1955-2012

Drought in Hawaii was resurgent in 2012, with 47.4 percent of the state affected by moderate to exceptional drought on January 3, growing to 73.2 percent by December 4. The state has been in drought for the last four years, with the December 4, 2012 peak approaching the peaks of 2008-2010. Several locations had record to near-record dry conditions in 2012, with Kahului recording the lowest rainfall for the year based on data from 1955-2012, and Honolulu having the fifth driest and Hilo eighth driest year in their 1950-2012 records. Annual rainfall at other U.S.-affiliated Pacific Island stations during 2012 was near or above normal.

Percent of normal precipitation for 2012 for Hawaii and U.S. Affiliated Pacific Island stations

Agricultural Belts:

The spatial pattern of drought this year closely overlaid the agricultural area of the U.S. heartland, and the excessive temperatures and lack of rain during the critical growing season severely reduced corn and soybean crop yield. The Primary Corn and Soybean agricultural belt, collectively, experienced the warmest and seventh driest March-August in 2012, resulting in the fourth most severe Palmer Z Index for the season (behind 1936, 1934, and 1988). The extreme severity of the dryness and evapotranspiration demand over the growing season resulted in a rapid increase in the percent area of this agricultural belt experiencing moderate to extreme drought (as defined by the Palmer Drought Index) and moderate to exceptional drought (for the Midwest and High Plains as defined by the USDM). By August 2012, about 89.3 percent of the Primary Corn and Soybean Belt was experiencing moderate to extreme drought (based on the Palmer Drought Index), surpassing all previous droughts except those in 1988 and the 1930s. The August-October rains in the eastern part of this region were beneficial and helped reduce the intensity of the drought there, but they did little to shrink the overall drought area for the entire region, with the value down to only 54.9 percent by the end of the year. By year's end, January-December 2012 ranked as the tenth driest year on record.

Primary Corn and Soybean Belt Temperature, March-August, 1895-2012 Primary Corn and Soybean Belt Precipitation, March-August, 1895-2012

Percent area of the Primary Corn and Soybean Belt in moderate to extreme drought, January 1900-December 2012 Primary Corn and Soybean Belt Palmer Z Index, March-August, 1900-2012

Primary Hard Red Winter Wheat Belt Precipitation, January-December, 1895-2012

The growing season (October-April) has started out on a dry note for much of the Winter Wheat agricultural belt. October-December 2012 ranked as the 27th driest October-December in the 1895-2012 record, with November 2012 ranking as the 13th driest November. For the smaller Primary Hard Red Winter Wheat belt, November 2012 ranked 23rd driest and October-December tenth driest. By year's end, January-December 2012 ranked as the ninth driest year on record for the Winter Wheat belt and third driest for the Primary Hard Red Winter Wheat belt.

River Basins:

Missouri River Basin precipitation, January-December, 1895-2012 Mississippi River and Tributaries North of Memphis, precipitation, January-December, 1895-2012

2012 Precipitation Ranks (out of 118 years) for the Major River Basins in the Contiguous U.S.: Calendar Year (January-December) and Water Year to Date (October-December)
River Basin Jan-Dec Oct-Dec
Pacific Northwest 11th wettest 10th wettest
California 56th driest 36th wettest
Great Basin 41st driest 35th wettest
Lower Colorado 24th driest 33rd driest
Upper Colorado driest 29th driest
Rio Grande 10th driest 5th driest
Texas Gulf Coast 41st driest 4th driest
Arkansas-White-Red 9th driest 11th driest
Lower Mississippi 48th driest 35th driest
Missouri 3rd driest 37th driest
Souris-Red-Rainy 35th driest 31st wettest
Upper Mississippi 10th driest 59th driest
Great Lakes 54th driest 26th wettest
Tennessee 38th driest 59th driest
Ohio 27th driest 55th wettest
South Atlantic-Gulf 53rd driest 46th driest
Mid-Atlantic 46th driest 37th wettest
New England 38th wettest 38th wettest

Several river basins have experienced unusually dry conditions during 2012, with the Upper Colorado having the driest year in the 1895-2012 record. As noted by the Midwest Regional Climate Center, drought has contributed to low water issues from the Great Lakes to the Missouri and Mississippi rivers, with navigation on the Mississippi River continuing to be a concern through December. The Missouri River basin had the third driest year in 2012 (behind 1934 and 1936), the Arkansas-White-Red River basin had the ninth driest year, and the Upper Mississippi and Rio Grande both ranked tenth driest. For the Mississippi River and all of its tributaries north of Memphis, Tennessee, 2012 ranked as the sixth driest year on record (behind 1934, 1936, 1976, 1988, and 1930). The aggregate PDSI for the Missouri basin reached the lowest value since the 1950s, while the aggregate PDSI for the broader Mississippi and its tributaries was the lowest since only 1988.

Historical Analogs:

Percent area of the contiguous U.S. in moderate-extreme drought, January 1900-December 2012

As seen in the National Drought Overview section, the percent area of the contiguous U.S. experiencing moderate to exceptional drought (based on the USDM) reached 65.5 percent in September, a record in the 13-year USDM history. The percent area of the contiguous U.S. experiencing moderate to extreme drought, based on the Palmer Drought Index (which goes 113 years), peaked at about 61.8 percent in July. This is only slightly larger than the peak percent area values of the 1950s drought decade and is the largest value since December 1939. So, in terms of total area covered by drought, the 2012 drought closely resembles the 1950s droughts.

The geographical pattern (location and intensity of dryness) of the 2012 drought can be compared to the patterns of previous droughts by using statistical tools such as the correlation coefficient and mean absolute difference. In the two tables below, the 2012 climate conditions (Palmer Z Index, Palmer Hydrological Drought Index [PHDI], temperature [Temp], precipitation [Precip]) were compared two different ways. In the table to the left, each month (January-December) of 2012 was compared individually to the previous years (1900-2011) to find the year with the closest match to each individual month (January closest match to January 2012, and February closest match to February 2012, and March closest match to March 2012, etc.). In the table to the right, the 2012 annual average values were compared to the annual average values for each of the previous years. No consistent pattern in historical analogs can be found in the monthly comparison (left-hand table) due to normal month-to-month variability (climatic noise). However, when the month-to-month variability is averaged out (by computing annual values as in the right-hand table), a consistent pattern becomes evident — the drought years 1955 and 1956 are the closest historical analogs to the geographical pattern of drought in 2012, and 1998 (the second warmest year on record) and 2006 (third warmest year on record) are the closest historical analogs to 2012 for the spatial temperature pattern.

Top 5 Analog Years to 2012 (each month January-December compared individually)
Rank* Z Index PHDI Temp Precip
1
1966 1955 1991 1904
2
1974 1956 2006 1901
3
1901 1920 1921 1917
4
2002 1918 1946 1931
5
1988 1963 1990 1974
* Rank: 1 = most similar to 2012.
Top 5 Analog Years to 2012 (annual values compared )
Rank* Z Index PHDI Temp Precip
1
1955 1955 1998 1955
2
1956 1956 2006 1966
3
1988 2000 1921 1956
4
1933 2006 1999 1980
5
1939 1981 1931 1988
* Rank: 1 = most similar to 2012.


[top]


Contacts & Questions
For additional, or more localized, drought information, please visit:

Global Snow & Ice

Issued: 15 January 2013

NH Snow Cover Extent

Snow Extent data were provided by the Global Snow Laboratory, Rutgers University. Period of record is 1966-2012 (47 years).

The timeseries to the right shows the mean Northern Hemisphere snow cover extent for winter (December-February) from 1967 through 2012. During the three month season in 2011/12, the Northern Hemisphere experienced its 14th largest (33rd smallest) snow cover extent on record at 590,000 square km (228,000 square miles) above the average of 45.2 million square km (17.5 million square miles). Northern Hemisphere winter snow cover extent has only changed slightly in the 47-year record, with a seasonal increase of about 0.1 percent per decade. By the spring season (March-May), the Northern Hemisphere snow cover extent contracted to a below-average extent for the time of year. The seasonal snow cover extent was 1.9 million square km (734,000 square miles) below the long-term average and ranked as the sixth smallest seasonal extent on record. Spring snow cover for the Northern Hemisphere is decreasing at an approximate rate of 2.2 percent per decade. More information on individual global snow and ice events during 2012 can be found in the Global Hazards report

Across North America during the 2011/12 winter, snow was limited, and the seasonal snowfall extent was the fourth smallest on record for the continent at 630,000 square km (243,000 square miles) below the average of 17.2 million square km (6.6 million square miles). This was the smallest winter snow cover extent since the winter of 1999/2000 and in stark contrast to the past two winter seasons, 2009/10 and 2010/11, which had the largest and third largest snow extents, respectively. The below-average snow cover extent for North America continued into spring. The spring snow extent for North America was 930,000 square km (359,000 square miles) below average and the third smallest value on record. For more information on U.S. snow and ice during 2012, please see the U.S. Snow and Ice report.

In Eurasia, snow cover extent during the 2011/12 winter was above average. The seasonal snow cover extent was 1.2 million square km (463,000 square miles) above the long-term average and ranked as the fourth largest on record, behind the winters of 1977/78, 2002/03, and 1971/72. By spring, the snow cover extent contracted to 1.0 million square km (386,000 square miles) below average and was the 12th smallest (35th largest) spring extent on record.

[ top ]


Sea Ice Extent

March 2012 Arctic Sea ice
Daily Arctic Sea ice extent through 2012
Data Source:NSIDC

Arctic sea ice, which is measured from passive microwave instruments onboard NOAA satellites, usually expands during the cold season to a March maximum, and then contracts during the warm season to a September minimum. According to data from the National Snow and Ice Data Center (NSIDC), the maximum Arctic sea ice extent during 2012 occurred on March 18th, which was 12 days later than average. The annual maximum extent of 15.24 million square km (5.88 million square miles) was 614,000 square km (237,000 square miles) below the 1979-2000 average and the ninth lowest in the satellite record. The nine smallest annual Arctic sea ice maximum extents have occurred between 2004 and 2012. On March 18th, most of the Arctic had near to slightly-above average sea ice coverage, with the exception of the Barents and Kara Seas and the Gulf of St. Lawrence. The March 2012 monthly average Arctic sea ice extent was 15.21 million square kilometers (5.87 million square miles), 3.42 percent below the 1979-2000 long-term average, and the ninth smallest March ice extent on record. This was the largest March Arctic sea ice extent since 2008, and one of the largest of the last decade.

September 2012 Arctic Sea ice
Arctic Sea Ice Extent on 16 September
Source:NSIDC

According to data from the NSIDC, on August 26th the Arctic sea ice extent dropped below the previous record low ice extent for the Arctic which occurred on September 18, 2007 at 4.17 million square km (1.61 million square miles). The sea ice continued shrinking until it dropped to 3.41 million square km (1.32 million square miles), reaching its annual minimum on September 16th. The 2012 annual minimum extent was 760,000 square kilometers (293,000 square miles) below the previous record minimum and 49 percent below the 1979-2000 average. During the Arctic sea ice melt season, between March 18th and September 16th, 11.83 million square kilometers (4.57 million square miles) of ice was lost. This marks the largest seasonal Arctic sea ice loss in the satellite record, surpassing the 10.65 million square km (4.11 million square miles) of ice loss during the 2008 melt season.

September's PIOMAS Arctic Ice Anomaly
Sea Ice Volume Anomaly
Source: UW's Polar Ice Center

When using Arctic sea ice extent to monitor the state of sea ice conditions across the Arctic, no information is available on the thickness of the ice. To compensate for this, the Polar Science Center at the University of Washington developed a modeled dataset to measure the volume of Arctic sea ice using the Pan-Arctic Ice Ocean Modeling and Assimilation System (PIOMAS). Sea ice volume is an important climate indicator because it depends on both ice thickness and extent and therefore more directly tied to climate forcing than extent alone. According to this dataset, Arctic sea ice volume reached a monthly low value during September 2012, at 3,400 km3, the smallest monthly sea ice volume on record. The previous record small Arctic sea ice volume for September occurred in 2011 at 4,200 km3. The September 2012 value is 72 percent lower than the mean over the 1979-2011 period, 80 percent lower than the maximum in 1979, and 2.0 standard deviations below the 1979-2011 trend.

The Southern Hemisphere sea ice extent reached its annual maximum extent on September 26th at 19.44 million square km (7.51 million square miles). This marked the largest annual maximum extent of Antarctic sea ice extent on record and surpassed the previous record of 19.36 million square km (7.47 million square miles) which occurred on September 21, 2006.

Arctic summer sea ice is shrinking much more rapidly than the rate at which Antarctic winter sea ice is expanding. Over the 1979-2012 record, the Arctic has experienced significant ice loss, while the growth of Antarctic sea ice has been slight. The September 2012 record low Arctic sea ice extent was 6.2 standard deviations below its 1979-2000 average, while the record large Antarctic sea ice extent was 2.1 standard deviations above its 1979-2000 average. Differences in hemispheric weather patterns, ocean currents, and geography partially account for these differing sea ice trends. A more detailed description of these differences is available through the NSIDC.

For further information on the Northern and Southern Hemisphere snow and ice conditions, please visit the NSIDC News page.

[ top ]

Upper Air

Troposphere

Lower Troposphere

Annual Lower Troposphere
January–
December
Anomaly Rank
(out of 34 years)
Record Years Decadal Trend
°C °F Year °C °F °C °F
UAH +0.16 +0.29 Coolest 26th 1984 -0.35 -0.63 +0.14 +0.25
Warmest 9th 1998 +0.42 +0.76
RSS +0.09 +0.16 Coolest 24th 1985 -0.36 -0.65 +0.13 +0.24
Warmest 11th 1998 +0.45 +0.81

Mid-troposphere

Annual Mid-troposphere
January–
December
Anomaly Rank
(out of 34 years*)
Record Years Decadal Trend
°C °F Year °C °F °C °F
UAH +0.01 +0.02 Coolest 17th 1984 -0.24 -0.43 +0.04 +0.08
Warmest 17th 1998 +0.42 +0.76
Ties: 1990
RSS +0.07 +0.13 Coolest 23rd 1985 -0.29 -0.52 +0.08 +0.14
Warmest 12th 1998 +0.43 +0.77
UW-UAH +0.07 +0.13 Coolest 24th 1984 -0.32 -0.58 +0.10 +0.19
Warmest 10th 1998 +0.52 +0.94
Ties: 2004
UW-RSS +0.12 +0.22 Coolest 25th 1985, 1984 -0.32 -0.58 +0.13 +0.24
Warmest 10th 1998 +0.51 +0.92
RATPAC* +0.20 +0.36 Coolest 47th 1965 -0.76 -1.37 +0.15 +0.27
Warmest 8th 2010 +0.48 +0.86
Ties: 2009

*RATPAC rank is based on 55 years of data

Stratosphere

Annual Stratosphere
January–
December
Anomaly Rank
(out of 34 years)
Record Years Decadal Trend
°C °F Year °C °F °C °F
UAH -0.42 -0.76 Coolest 3rd 2008 -0.48 -0.86 -0.37 -0.67
Warmest 32nd 1982 +1.04 +1.87
RSS -0.41 -0.74 Coolest 1st 2012 -0.41 -0.74 -0.30 -0.54
Warmest 34th 1992 +0.96 +1.73

Background Information

Temperatures above the Earth's surface are measured within the lower troposphere, middle troposphere, and stratosphere using in-situ balloon-borne instruments (radiosondes) and polar-orbiting satellites (NOAA's TIROS-N). The radiosonde and satellite records have been adjusted to remove time-dependent biases (artificialities caused by changes in radiosonde instruments and measurement practices as well as changes in satellite instruments and orbital features through time). Global averages from radiosonde data are available from 1958 to present, while satellite measurements date back to 1979.

The mid-troposphere temperatures are centered in the in the atmospheric layer approximately 3–10 km [2–6 miles] above the Earth's surface, which also includes a portion of the lower stratosphere. (The Microwave Sounding Unit [MSU] channel used to measure mid-tropospheric temperatures receives about 25 percent of its signal above 10 km [6 miles].) Because the stratosphere has cooled due to increasing greenhouse gases in the troposphere and losses of ozone in the stratosphere, the stratospheric contribution to the tropospheric average, as measured from satellites, creates an artificial component of cooling to the mid-troposphere temperatures. The University of Washington (UW) versions of the UAH and RSS analyses attempt to remove the stratospheric influence from the mid-troposphere measurements, and as a result the UW versions tend to have a larger warming trend than either the UAH or RSS versions. For additional information, please see NCDC's Microwave Sounding Unit page.

The radiosonde data used in this global analysis were developed using the Lanzante, Klein, Seidel (2003) ("LKS") bias-adjusted dataset and the First Difference Method (Free et al. 2004) (RATPAC). Additional details are available. Satellite data have been adjusted by the Global Hydrology and Climate Center at the University of Alabama in Huntsville (UAH). An independent analysis is also performed by Remote Sensing Systems (RSS) and a third analysis has been performed by Dr. Qiang Fu of the University of Washington (UW) (Fu et al. 2004)** to remove the influence of the stratosphere on the mid-troposphere value. Global averages from radiosonde data are available from 1958 to present, while satellite measurements began in 1979.

References

Wildfires


Please note: Material provided in this report is chosen subjectively and included at the discretion of the National Climatic Data Center (NCDC). The ability to report on a given event is limited by the amount of information available to NCDC at the time of publication. Data included in this report are preliminary unless otherwise stated. Links to supporting information are valid at the time of publication, but they are not maintained or changed after publication.


Updated: 07 January 2013


2000-2012 Annual U.S. Wildfire Counts
2000–2012 Annual U.S. Wildfire Counts
Data Source: NIFC

2012 marked the warmest year on record for the contiguous U.S. in a period of record that dates back to 1895. The record-breaking warmth was paired with exceptional dryness across much of the nation. Drier-than-average conditions were experienced from the Rockies to the East Coast. Nebraska and Wyoming each had their driest year on record. Meanwhile, wetter-than-average conditions existed in the Pacific Northwest, the central Gulf Coast, and New England. By September's end, the percentage of the country experiencing moderate-to-exceptional drought peaked at about 64.6 percent for the contiguous U.S. (about 54 percent including Alaska, Hawaii, and Puerto Rico), according to the U.S. Drought Monitor. The wildfire activity of 2012 supplanted 2011's rank as third most acres burned, behind the 2006 and 2007 seasons. Although the number of fires was below-average, the size of the fires was notably increased. The annual fire size of 137.1 acres was the most since 2000 for any January through December period, which was about 1.5 times the 10-year average (based on 2001-2010). Large wildfires occurred in New Mexico (largest in state history), Colorado (second largest in state history), and Oregon (largest since the 1860s). Overall, the number of fires remained below-average for 19 of the past 20 months (every month since May 2011, with the exception of January 2012). The month of January saw elevated wildfire activity as the result of combined warmth and dryness in the Great Plains, and a lack of snow pack having left the grasslands of the High Plains exposed to strong winds.

Year-to-Date Wildfire Statistics*
January–December Totals Rank
(out of 13 years)
Record 2000-2010
Average
Value Year
Acres Burned 9,221,639 3ʳᵈ Most 9,873,745 2006 6,612,363
11ᵗʰ Least
Number of Fires 67,265 10ᵗʰ Most 96,385 2006 77,951
4ᵗʰ Least
Acres Burned per Fire 137.1 Most on Record 137.1 2012 85.2
13ᵗʰ Least

*Data Source: The National Interagency Fire Center (NIFC)


Through December 28th, the nationwide number of fires year-to-date reached 67,265 fires which was the fourth least annual number of wildfires since 2000. Texas experienced the most number of wildfires of any state during 2012 with more than 10,600 fires (about 16 percent of the national total). Nationally, the amount of acres burned was 9,221,639 during 2012, which represents about 1.5 times the 10-year average (based on 2001-2010) of 6,534,250 acres burned. The month of August saw notable wildfire activity, when the fire size reached 523.4 acres per fire (the highest for any August in the 2000-2012 record) and the acres burned in August were nearly equal to the acres burned from January through July 2012. Idaho wildfires burned the most acres of any state during the year, with over 1.5 million acres (about 17 percent of the national total). Oregon and Montana followed closely with each having in excess of 1.2 million acres burned within their respective states. During 2012 the damages from wildfires across the country will top one billion U.S. dollars.

Acres Burned during 2012
Acres Burned during 2012
Compared to 2001–2010 Average
Number of Fires during 2012
Number of Fires during 2012
Compared to 2001–2010 Average

Cumulative wildfires and prescribed burns for contiguous U.S. from January through October 2012Cumulative wildfires for contiguous U.S.
from January 1 through October 31, 2012
Source: NASA

Records maintained by the National Interagency Fire Center (NIFC) and NASA both indicate that 2012 was an extraordinary year for wildfires in the United States. The visualization in the satellite image depicts total fires that burned between January 1st and October 31st as detected by the MODIS instruments. Yellow and orange areas indicate fires that were more intense and had a larger area of active burning, which were likely produced by wildfires. Red areas represent the lower intensity of fires typically associated with prescribed burns, which are used for agricultural or ecosystem management purposes.


Significant Events in 2012

Please note, this is a list of select fires that occurred during the year. Additional fire information can be found through Inciweb.


Whitewater-Baldy Complex Fire in New Mexico on 06 June 2012Whitewater-Baldy Complex Fire in New Mexico
on 06 June 2012
Source: USFS Gila National Forest

Two large wildfires which began in mid-May in New Mexico, the Baldy Fire and the Whitewater Fire, merged to create the Whitewater-Baldy Fire complex. Both fires were ignited by lightning strikes in the very dry Gila National Forest in western New Mexico and resulted in the charring of nearly 300,000 acres by late June. The amount of smoke from the fire was unusually high due to the dense coniferous forests which were impacted, causing very low air quality conditions across a large area of western New Mexico. The fire surpassed the Las Conchas Fire of 2011, which destroyed over 156,500 acres, as the largest fire in New Mexico history. Aerial seeding and mulching of the high-severity burn areas were conducted as part of Burn Area Emergency Rehabilitation that concluded in October when most of the trails reopened to the public.

High Park Fire in Colorado on 18 June 2012High Park Fire in Colorado on 18 June 2012
Source: USGS/NASA

Of Colorado's 252,000 acres consumed by wildfires during 2012, more than half were lost in the month of June as part of the state's worst wildfire season in a decade. Two devastating fires erupted that month including the High Park Fire, which destroyed 259 homes and nearly 87,300 acres, followed by the Waldo Canyon Fire, which destroyed 346 homes and more than 18,000 acres. One fatality was attributed to the High Park Fire — the second largest fire in Colorado's history. The Waldo Canyon Fire was deemed the most destructive fire in the state's history and resulted in two deaths.

Oregon wildfires during July 2012Oregon wildfires during July 2012
Source: NASA

As one of three major eastern Oregon wildfires during July, the Long Draw Fire scorched almost 560,000 acres of short grass and sagebrush to become the state's largest fire since the 1860s. Ignited by lightning in the Owyhee River Canyon, the wildfire destroyed rangeland, livestock, and habitats for prairie wildlife (rabbits, coyotes, grouse) in the remote area of southeast Oregon. Close to 800 firefighters with aerial support battled two other blazes, which threatened the town residents of Frenchglen (Miller Homestead Fire fueled by dry peat) and Westfall (Bonita Complex Fire fueled by sage and juniper).

Idaho wildfires during August 2012Idaho wildfires during August 2012
Source: NASA Earth Observatory

Intense wildfires were concentrated in the beetle-killed forest lands of Idaho. Large fires actively burned from mid-summer through autumn. Heavy smoke from the various fires resulted in adverse air quality for area residents. Three notable fires collectively blazed over 669,200 acres of national forest during 2012, which represented about 45 percent of the state's annual total. The Halstead Fire scorched nearly 181,800 acres (late July-late October), the Mustang Complex consumed more than 340,600 acres between late July and early November, and the Trinity Ridge Fire destroyed over 146,800 acres while raging from early August through mid-October.


Citing This Report

NOAA National Climatic Data Center, State of the Climate for Annual 2012, published online December 2012, retrieved on September 18, 2014 from http://www.ncdc.noaa.gov/sotc/2012/13.