Long-term extreme and exceptional drought in the south Plains and Southwest receded substantially in the week that ended Aug. 20, while moderate drought returned to parts of the Corn Belt, according to the U.S. Drought Monitor.
“Until recently, rain has been falling in several areas experiencing long-term drought, including the central and southern Plains and the Southwest,” said Brad Rippey, a meteorologist in the U.S. Department of Agriculture’s Office of the Chief Economist. “At the same time, 1- to 2-month rainfall deficits remain a concern in some of the nation’s key crop production areas, including parts of the Midwest. As a result, the latest U.S. Drought Monitor, valid August 20, indicates a general reduction in the severity of long-term drought in the south-central and southwestern U.S., but an expansion of short-term drought in the Corn Belt.”
Overall, moderate to exceptional drought (D1-D4) coverage in the 48 contiguous states increased to 45.61 percent, about a third of a percentage point up from 45.26 percent a week earlier, but nearly 20 percentage points below the peak of 65.45 percent in September 2012. Moderate drought (D1) expanded to cover 10 percent of Minnesota in the past week and still covers 35 percent of Iowa and 15 percent of Missouri. Moderate drought also expanded in Wisconsin, Texas and Louisiana this week.
Rippey noted that on August 20, exceptional drought (D4) covered just 1.32 percent of the continental U.S., down nearly three-quarters of a percentage point from a week ago to the lowest value since July 17, 2012. Similarly, coverage of extreme to exceptional drought (D3 to D4) fell more than a percentage point to 10.54 percent of the lower 48 states, the smallest area since July 3, 2012.
The portion of the U.S. corn production area in drought has been edging upward in recent weeks, from 17 to 25 percent between July 9 and August 20, Rippey said. The increase has been largely due to the return of drought to parts of the western Corn Belt. Soybeans in drought have also increased in the last six weeks, from 8 to 16 percent. Hay (33 percent) and cattle in drought (46 percent) were both unchanged from last week.
Rippey also observed that after making its first-ever appearance in Alaska on July 23, severe drought (D2) expanded during the week ending August 20 and now covers nearly 7 percent of the state. The USDA reported that Alaska’s topsoil moisture was rated 70 percent very short to short on August 18, and that pastures were rated 40 percent very poor to poor.
The western fire season continued to be active. “Wildfires remain a problem in parts of the West,” said Mike Brewer, this week’s U.S. Drought Monitor author. “The National Interagency Fire Center reported 51 active, large wildfires on August 20, up from last week. Large fires continue to burn in 10 western states including Idaho, where the Elk Fire has consumed over 130,000 acres of vegetation, an increase of over 30,000 acres this week. … [T]he cost of battling wildfires in 2013 has now exceeded $1 billion.”
U.S. Drought Monitor authors synthesize many drought indicators into a single map that identifies areas of the country that are abnormally dry (D0), in moderate drought (D1), in severe drought (D2), extreme drought (D3) and exceptional drought (D4). The map is released each Thursday based on data through the previous Tuesday morning.
The U.S. Drought Monitor map is jointly produced by the National Drought Mitigation Center at the University of Nebraska-Lincoln, the National Oceanic and Atmospheric Administration, the USDA, and about 350 drought observers across the country. Brewer is with NOAA’s National Climatic Data Center.
Statistics for the percent area in each category of drought are automatically added to the U.S. Drought Monitor website each week for the entire country and Puerto Rico, for the 48 contiguous states, for each climate region, and for individual states. U.S. Drought Monitor data online goes back to January 2000.
http//drought.unl.edu/MonitoringTools/USDroughtMonitor/DroughtMonitorTips.aspx
U.S. Drought Monitor map, statistics and narrative summary: http://droughtmonitor.unl.edu
Drought Impact Reporter: http://droughtreporter.unl.edu
USDA’s weekly “Agriculture in Drought” analysis:
http://www.usda.gov/oce/weather/Drought/AgInDrought.pdf
National Climatic Data Center’s State of the Climate Drought Summary: http://www.ncdc.noaa.gov/sotc/drought/
U.S. Monthly Drought Outlook:
http://www.cpc.ncep.noaa.gov/products/expert_assessment/monthly_drought.html
U.S. Seasonal Drought Outlook:
http://www.cpc.ncep.noaa.gov/products/expert_assessment/seasonal_drought.html
-- Kelly Helm Smith, National Drought Mitigation Center