NOAA's National Centers for Environmental Information
 |
|
U.S. Drought
| As the year began, moderate to extreme drought covered one-third* of the contiguous United States including much of the eastern seaboard and northwestern U.S. The combination of generally warmer- and drier-than-average conditions led to an increase in the areal coverage to slightly more than 50 percent during the summer months, largely due to a rapid intensification of drought in the Southwest. This value fell to 35 percent by the end of December as precipitation from landfalling tropical systems and a more active storm track helped alleviate drought in much of the eastern part of the country. |
|
The most extensive national drought coverage during the past 100 years (the period of instrumental record) occurred in July 1934 when 80 percent of the contiguous U.S. was in moderate to extreme drought. Although the current drought and others of the 20th century have been widespread and of lengthy duration, tree ring records indicate that the severity of these droughts was likely surpassed by other droughts including that of the 1570s and 1580s over much of the western U.S. and northern Mexico. |
|
On a national scale,
long-term drought (as measured by the Palmer Drought Index) rapidly
expanded during the first half of 2002 to reach a peak area
coverage of about 39% of the country in the severe to extreme
categories by July. Heavy rains from tropical systems and frontal
storms fell over some of the drought areas during the late summer
and fall, resulting in a decrease in the drought area to about 22%
of the contiguous U.S. by the end of December.
The percent of the country in the severe to extreme wet spell categories (as measured by the Palmer Drought Index) fluctuated between 0 and 4% during most of the year, eventually rising to about 7% by the end of December. |
| The 2002 national drought had its origins in late 1999. At its peak in July 2002 this drought, when compared to other droughts of the 20th Century, was as extensive as the major droughts of the last 40 years, but not as large as the "dust bowl" droughts of the 1930s and 1950s. The duration of the current national drought (about 37 months) is longer than the duration of the 1970s drought and about as long as the late 1980s drought. |
|
|
|
The 2002 national
drought was focused in several areas during the year. Abnormal
dryness, which plagued the parts of the Southwest since mid-2001,
worsened in that region in 2002 and spread into the central Plains
during the spring
(March-May). Record dry conditions from 2001 continued into
early 2002 in the eastern U.S., peaking in February
and contributing to the
fourth driest February, nationally, in the 108-year record. The
2001-2002 rainy season in the West
region (California and Nevada) dried out beginning in January,
with the drier than normal conditions continuing
through October. Drier than normal weather which developed in
the Pacific Northwest during the spring persisted
through November. Areas of severe short-term drought developed
in the Ohio Valley and southern Great Lakes during the summer
(June-August) and late
fall.
The drought severely impacted many areas of the country. Drought emergencies were declared and water restrictions implemented in many cities and counties. The impacts included depleted reservoirs, dry wells, and desiccated crops and pastures. Dust storms roared in Montana, Colorado, and Kansas, bringing back memories of the 1930s. The largest wildfires in state history occurred in Colorado, Arizona, and Oregon this year. |
| Persistent dryness in the Southwest region resulted in the driest September-August in the 108-year record. The extreme recent dryness, coupled with the persistent dryness of the last three years, resulted in a record low regionwide Palmer Hydrological Drought Index. Several states in the region also experienced the driest September-August on record, including Colorado, Arizona, and Nevada. |
|
|
|
| The 2001-2002 rainy season (November-March) for the West region started out wet, but it turned dry in January. The region experienced below normal precipitation consistently for the next ten months, resulting in the driest January-October in the 108-year record. |
|
|
| In the Pacific Northwest the 2001-2002 rainy season (October-April) was generally wet, giving the region overall a near average hydrologic year (October-September). Subnormal rainfall fell starting with the 2002 dry season, however, resulting in the driest May-October in the 108-year record. |
|
|
|
During late 2001 and
early 2002, extreme dryness afflicted almost the entire eastern
seaboard. This was the latest dry episode in a long-term drought
which started, generally, in
July 1998 for the Northeast
and
May 1998 for the Southeast.
September 2001-February 2002 ranked as the second driest such six-month period for the Northeast. A four-month wet spell followed, but short-term drought struck again during the following two months giving the region the third driest July-August in the 108-year record. |
|
|
| In the Southeast, October 2001-May 2002 ranked as the seventh driest October-May in the 108-year record. Precipitation deficits in this region have been much below the long-term mean for the last four years. |
|
|
|
On a statewide basis, the Carolinas were the epicenter of the 2002 drought in the Southeast. The states from Virginia to Georgia had their driest August-July on record this year. The extreme dryness of this period, coupled with the persistent dryness of much of the last four years, resulted in a near-record dry statewide Palmer Hydrological Drought Index for both North and South Carolina. |
|
|
| New Jersey was the drought epicenter in the Northeast. This state, along with Connecticut, had the driest July-February on record this year, while Maryland had the driest October-February. Wetter conditions prevailed in Maine in early 2002 following the driest year (2001), statewide, in the 108-year record. But the severe dryness meant the state started out 2002 with the driest statewide Palmer Hydrological Drought Index on record. Severe drought plagued the state again during the summer with the driest August on record. |
|
|
|
|
Nebraska was the epicenter of drought in the central Plains. Precipitation shut off over much of the state beginning in December 2001, resulting in the driest December-July in the 108-year record. In the southern Plains, Texas was dogged by drought in the Trans-Pecos region and in Deep South Texas. While other parts of the Lone Star State received abundant rainfall, Deep South Texas (climate division 10) had the driest September-August on record in 2002. The Trans Pecos region (climate division 5) has been experiencing drought for much of the last five years. |
|
|
| The western United States suffered from drought for much of the year. In north central Montana (climate division 3), several years of subnormal precipitation culminated in a Palmer Hydrological Drought Index that, by early 2002, had reached the lowest levels seen in the last 100 years. With duststorms swirling, local experts were comparing the parched landscape to the Dust Bowl years of the 1930s. |
|
|
Dry conditions have persisted in Wyoming since 1999. This prolonged dryness, coupled with record dry conditions during August 2001-July 2002, gave the state the driest Palmer Hydrological Drought Index in the last 100 years. |
|
|
| Colorado was another western state hit hard by drought this year. The persistent dryness from September 2001 to August 2002, aggregated across the state, was so severe that, not only did it set a new record for September-August, it broke the old record by a huge margin. Numerous seasonal records were set for the state, including the driest December-August. The unprecedented moisture deficits resulted in a statewide Palmer Hydrological Drought Index that rapidly reached record drought intensity. |
|
|
|
|
Record dryness occurred in the intermountain basin this year. On a statewide basis, Utah received below normal precipitation each of the first eight months of 2002, giving the state the driest January-August in the 108-year record. This is a marked departure from the unusually wet conditions that have characterized much of the last two decades. |
|
|
| More detailed analyses are available for the following states and regions: |
|