NCDC: U.S. Regional Drought Watch

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Climate of 2001 - December
U.S. Regional Drought Watch

National Climatic Data Center, 15 January 2002

Global Analysis / Global Regional / United States / U.S. Drought / Extreme Events / Climate Indices
Use these links to access detailed analyses of Global and U.S. data.

Regional Drought Overview / Western U.S. Drought / Eastern U.S. Drought / Additional Contacts / Questions

Regional Overview

Beneficial rain and snow during October through December brought an end to short-term drought over much of the western U.S., however long-term drought continued to plague much of the region, especially along the Rocky Mountains. December was dry across parts of the northern Rockies, Gulf Coast, and northern and central Plains. December marked the third consecutive dry month along the eastern seaboard, further intensifying long-term drought conditions. Most of the Alaska stations and the primary stations in northern Hawaii were dry during December. This overall pattern is evident in the following indicators:

the Palmer Indices and Standardized Precipitation Index,
the runoff and soil moisture conditions as calculated by the National Weather Service,
the percent of normal precipitation map for December,

larger image
the percent of average precipitation map for the hydrologic year thus far (October 1, 2001 - January 2, 2002), and the percent of average basin snow water content map for early January, for the SNOTEL stations in the western mountains provided by the USDA Water and Climate Center,
maps showing the departure from normal of the number of days with precipitation for December and the longest consecutive number of days with no precipitation for December,

Click here for map showing Departure from Normal Number of Days with Measureable Precipitation for December 2001

Click here for map showing Maximum Number of Consecutive Days with No Measureable Precipitation for December 2001

the statewide precipitation ranks for December (short-term) and October-December, July-December, and January-December (longer-term), and

Click here for map showing Statewide Precipitation Ranks for October-December 2001

Click here for map showing Statewide Precipitation Ranks for January-December 2001

the USGS December daily streamflow maps.

Two other drought-related monitoring tools are the Vegetation Health Index and the Keetch-Byram Drought Index:

NOAA satellite observations of vegetation health from early January reveal continued stress on vegetation in parts of the southwestern U.S., including western Texas. The VHI product becomes less useful as vegetation goes dormant during the winter.
The Keetch-Byram Drought Index (KBDI) is used by the National Interagency Fire Center to monitor the risk of wildfires. The end of December KBDI showed dry conditions along the eastern seaboard and from the northern Plains to the intermountain West. The Forest Service fire danger analysis indicated a continuing risk of wildfires over parts of the mid-Atlantic and Southeast states by the end of December.

Western U.S. Drought

A moist Pacific flow continued to bring wet winter storms to a large part of the western U.S. during December, ending short-term meteorological drought over much of the Pacific Northwest and West regions. The Pacific Northwest had the 18th wettest October-December on record during 2001, bringing well above normal water content to the mountain snowpack. However, long-term drought remained, with many reservoirs still well below normal in the region and 2001 closing as the 27th driest year on record (see graph to right below). Highlights:

Declared drought emergencies continued in three western states (Washington, Oregon, and Idaho).
Conditions improved in Idaho with above-normal 3-month precipitation, mountain snowpack, and modeled soil moisture. But the drought is far from over, as reservoir levels are still low with combined storage for Idaho's 21 reservoirs and lakes at third lowest since 1958. The Salmon Falls Reservoir (south of Twin Falls in central Idaho) level is the lowest since December 1962.
December precipitation brought short-term relief to western Texas, however severe long-term moisture deficits persisted.

Click here for graph showing Pacific Northwest region January-December precipitation for 1895-2001

Click here for graphic showing Pacific Northwest Region Precipitation Anomalies, January 1998 - December 2001

Click here for graphic showing West Region Precipitation Anomalies, January 1998 - December 2001

Much of the western rain and snow of the past three months have bypassed Montana. The state has suffered from dry conditions for the last three years, causing many wells to go dry, with 2001 ranking as the eleventh driest year on record statewide. The last five months have been persistently dry, giving the state the fourth driest August-December on record (see graph below left). The December 2001 statewide Palmer Drought Index is nearly as severe as the droughts of the 1930's (see graph below right). In nearby Wyoming, drought has drained reservoirs and stunted shrubs used by deer and antelope for winter forage, putting the wildlife at risk.

Click here for graphic showing Montana Statewide Precipitation Anomalies, January 1998 - December 2001

Precipitation Ranks (out of 107 years)
for Montana, 2001
Period	Rank
Dec	36^th driest
Nov-Dec	23^rd driest
Oct-Dec	18^th driest
Sep-Dec	18^th driest
Aug-Dec	4^th driest
Jul-Dec	18^th driest
Jun-Dec	39^th driest
May-Dec	18^th driest
Apr-Dec	18^th driest
Mar-Dec	17^th driest
Feb-Dec	14^th driest
Jan-Dec	11^th driest

Click here for graphic showing Montana Statewide August-December Precipitation, 1895-2001

Click here for graphic showing Montana Statewide Palmer Drought Index, January 1895 - December 2001

Eastern U.S. Drought

December brought the third consecutive month of very dry conditions to the east coast. In the Northeast region, 2001 had the second driest October-December on record while it was the third driest for the Southeast.

Click here for graphic showing Southeast Region Precipitation Anomalies, January 1998 - December 2001

Click here for graphic showing Southeast Region Precipitation, October-December, 1895-2001

With reservoir storage and ground water supplies well below seasonable averages and, in some cases, at record low levels, the Delaware River Basin Commission declared a drought emergency in mid-December in the 13,539 square-mile watershed which drains portions of New York State, Pennsylvania, New Jersey, and Delaware.

Click here for graphic showing Northeast Region Precipitation Anomalies, January 1998 - December 2001

Click here for graphic showing Northeast Region Precipitation, October-December, 1895-2001

Precipitation Ranks (out of 107 years)
for the Northeast Region, 2001
Period	Rank
Dec	22^nd driest
Nov-Dec	8^th driest
Oct-Dec	2^nd driest
Sep-Dec	8^th driest
Aug-Dec	4^th driest
Jul-Dec	3^rd driest
Jun-Dec	7^th driest
May-Dec	7^th driest
Apr-Dec	2^nd driest
Mar-Dec	8^th driest
Feb-Dec	6^th driest
Jan-Dec	4^th driest

As shown on the Palmer Hydrological Drought Index map to the right, the drought in the east has two epicenters of severity: Maine and South Carolina.

Maine had the driest year in 2001 and also the driest rank for several seasons (see table below).
The persistent lack of precipitation resulted in a rapid increase in drought severity, giving the state the worst Palmer Drought Index on record by the end of the year.
The drought in Maine has resulted in record low well levels and streamflows at many places with uncounted wells going dry, and Governor King urgently requested citizens to conserve water. By mid - December, some public water utilities had imposed conservation measures, and several were asking for voluntary action by consumers.

Click here for map showing Palmer Hydrological Drought Index, December 2001

Click here for graphic showing Maine Statewide Precipitation, January-December, 1895-2001

Click here for graphic showing Palmer Drought Index for Maine, January 1900 - December 2001

Precipitation Ranks (out of 107 years)
for Maine, 2001
Period	Rank
Dec	7^th driest
Nov-Dec	1^st driest
Oct-Dec	1^st driest
Sep-Dec	4^th driest
Aug-Dec	1^st driest
Jul-Dec	1^st driest
Jun-Dec	2^nd driest
May-Dec	1^st driest
Apr-Dec	1^st driest
Mar-Dec	1^st driest
Feb-Dec	1^st driest
Jan-Dec	1^st driest

South Carolina had the driest October-December, August-December, and July-December, and the second driest year on record in 2001, giving rise to a statewide Palmer Drought Index which is comparable in severity to the worst droughts of the last 100 years. As noted by the state Department of Natural Resources,

Low streamflows and lack of precipitation have caused many South Carolina lake levels to continuously drop.
Ground water levels have also significantly fallen. Since the drought began in 1998, the annual mean water level in a shallow sand monitoring well in Aiken County has dropped approximately 2 feet (0.61 meter).
According to the S.C. Forestry Commission, the drought contributed to the second worst southern pine beetle outbreak since records began in the early 1960s, with timber losses due to the beetles estimated at $76 million during 2001.
The Forestry Commission also noted that 2001 had the worst fall fire season since 1991, with 2,308 fires burning 12,565 acres (5085 hectares) from September through December. This is double the average number of fires and four times the number of acres normally burned during the four-month fall season.

Click here for graphic showing South Carolina Statewide Precipitation, January-December, 1895-2001

Click here for graphic showing Palmer Drought Index for South Carolina, January 1900 - December 2001

Precipitation Ranks (out of 107 years)
for South Carolina, 2001
Period	Rank
Dec	9^th driest
Nov-Dec	4^th driest
Oct-Dec	1^st driest
Sep-Dec	3^rd driest
Aug-Dec	1^st driest
Jul-Dec	1^st driest
Jun-Dec	3^rd driest
May-Dec	3^rd driest
Apr-Dec	2^nd driest
Mar-Dec	4^th driest
Feb-Dec	3^rd driest
Jan-Dec	2^nd driest

Additional Contacts:

Damage due to the drought has been summarized by NOAA and the Office of Global Programs in the Climatological Impacts section of the Climate Information Project. Crop impact information can be found at the USDA NASS (National Agricultural Statistics Service) and Weekly Weather and Crop Bulletin pages. Drought statements by local National Weather Service Offices can be found at the NWS Hydrologic Information Center. Drought threat assessments and other information can be found at NOAA's Drought Information Center. Additional drought information can be found at the National Drought Mitigation Center, the USDA's National Agricultural Library, the interim National Drought Council, and the NOAA Paleoclimatology Program. The following states have set up web pages detailing current drought conditions and/or their plans to handle drought emergencies:

Delaware - Delaware River Basin (DE-NJ-NY-PA) - Florida Panhandle - Georgia - Hawaii - Idaho - Kentucky - Maryland - Missouri - Montana-1 - Montana-2 - Nebraska - New Jersey - New Mexico - North Carolina - Oklahoma-1 - Oklahoma-2 - Oregon-1 - Oregon-2 - Pennsylvania-1 - Pennsylvania-2 - South Carolina - Texas - Vermont - Washington - Wyoming

For additional information on the 2001 wildfire season please see the National Interagency Fire Center web site or the U.S. Forest Service Fire and Aviation web site.

NCDC's Drought Recovery Page shows the precipitation required to end or ameliorate droughts and the probability of receiving the required precipitation.

Additional climate monitoring graphics can be found at the Climate Prediction Center's monitoring pages:

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For all climate questions other than questions concerning this report, please contact the National Climatic Data Center's Climate Services Division:

Climate Services Division
NOAA/National Climatic Data Center
151 Patton Avenue
Asheville, NC 28801-5001
fax: 828-271-4876
phone: 828-271-4800
email: ncdc.info@noaa.gov

For further information on the historical climate perspective presented in this report, contact:

Richard Heim
NOAA/National Climatic Data Center
151 Patton Avenue
Asheville, NC 28801-5001
fax: 828-271-4328
email: Richard.Heim@noaa.gov

-or-

Jay Lawrimore
NOAA/National Climatic Data Center
151 Patton Avenue
Asheville, NC 28801-5001
fax: 828-271-4328
email: Jay.Lawrimore@noaa.gov

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NCDC / Climate Monitoring / Climate of 2001 / December / Search / Help

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Last Updated Tuesday, 12-Jul-2005 09:00:05 EDT by Richard.Heim@noaa.gov
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