NCDC / Climate Monitoring / Climate of 2005 / Annual / Drought / Help
Climate of 2005 Annual Review U.S. Drought
National Climatic Data Center, 13 January 2006
|
The data presented in this drought report are preliminary. Ranks, anomalies, and percent areas may change as more complete data are received and processed.
National Drought Overview
|
*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.
|
The most extensive national drought coverage during the past 100 years (the period of widespread reliable instrumental records) 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.
|
Regional Drought Overview
At its peak last year, the 2004 drought affected about two-thirds of the West (Rocky Mountains to West Coast). Abundant rain and record snowpacks from winter storms beginning in September 2004 brought relief to the Southwest, with only about 19 percent of the West affected by moderate to extreme drought by the end of January 2005.
|
While the West was experiencing wet conditions, the drought focus shifted to the middle part of the country. Starting in the spring, unusually dry weather settled in over the Midwest and southern Plains.
|
Dryness occurred throughout the spring, fall, early winter, and part of summer across much of Arkansas, Illinois, Missouri, Oklahoma, and Texas. Especially hard-hit were northern Illinois and the Arklatex region (southwestern Arkansas, southeastern Oklahoma, northeastern Texas), both of which experienced the driest year in the 111-year record.
|
|
Low streams, reservoirs, and stock ponds, depleted soil moisture (June, October), ravaged pastures and rangeland, and numerous wildfires prompted governors and the USDA to declare drought disasters in parts or all of several states (Arkansas, Illinois, Iowa, Kansas, Missouri, Texas, and Wisconsin). National corn, soybean, and wheat crop yields were below last year's records, but still above average. By the end of the year, a band of moderate to extreme drought stretched almost continuously from the Texas Gulf coast to Upper Michigan.
|
|
Parts of the Northeast experienced short-term dryness during early summer, with dryness returning to much of the Eastern Seaboard and Pacific Northwest during the late summer to early fall. Three states (Georgia, Maryland, South Carolina) had the driest September in the 111-year record, and six states (Delaware, Maryland, Oregon, South Carolina, New Jersey, Virginia) had the tenth driest, or drier, August-September.
|
|
|
|
The year ended with a very dry month from the Southwest across the southern Plains to the Ohio Valley and eastern Great Lakes. Several states from the Southwest to Lower Mississippi Delta had the tenth driest, or drier, December, including Arizona and Arkansas with the driest December in the 111-year record. November-December marked a turnaround in moisture conditions for the Southwest, where 12 months ago the weather was unusually wet. An examination of USDA snowcourse/snotel station data in Arizona revealed that 31 of 33 sites, or 94% of them, were snow free at the end of the year, the most snow-free locations in at least the past 40 years.
December capped a three-month period of exceptionally dry weather for the southern Plains, with Arkansas and the Arklatex experiencing the driest October-December on record. Dry, windy, and warmer-than-normal weather contributed to the outbreak of numerous grassfires in Oklahoma, Texas, Arkansas, and New Mexico.
|
Pre-instrumental Drought Perspective
Tree ring records provide a useful paleoclimatic index that extends our historical perspective of droughts centuries beyond the approximately 100-year instrumental record. Several paleoclimatic studies have shown that droughts as severe or worse, both in magnitude and duration, than the major 20th century droughts have occurred in the U.S. during the last thousand years. The following paleodrought reports have been prepared by the NOAA/NCDC Paleoclimatology and Climate Monitoring branches during 2005:
|
- 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
|
NCDC / Climate Monitoring / Climate of 2005 / Annual / Drought / Help
|