Rains across the Midwest improved drought in the past week, especially in areas where the ground has thawed and moisture could soak in, according to the March 12 U.S. Drought Monitor map and narrative.
The map showed improvements in all categories of drought, with the total area of the country in moderate drought or worse declining to 43.3 percent from 44.93 percent a week before, according to statistics released with the map.
In the Midwest, the area in moderate drought or worse decreased to 35.54 percent from 45.74 percent the week before. Missouri and Iowa saw the largest improvements, but in Illinois, Wisconsin and Minnesota, where the ground was still frozen, significant precipitation did not translate into widespread drought relief.
According to local observers, “the frozen ground (10-20 inches of frozen soils) is preventing deep soil moisture recharge,” said Matthew Rosencrans, this week’s U.S. Drought Monitor author. “Streams and rivers rose and fell rapidly, indicting excessive runoff and lack of penetration, along with some reports of basement flooding as the water cannot go into the soil.” Rosencrans is a meteorologist at the National Oceanic and Atmospheric Administration’s Climate Prediction Center.
Drought shifted in the Plains, with only a slight net reduction in intensity. South Dakota showed both better and worse conditions in different parts of the state. Exceptional drought receded slightly in Nebraska, which has been the epicenter of lingering drought that began in summer 2012. Additional improvements occurred in Kansas, Oklahoma and the Texas Panhandle, although exceptional drought expanded over southern Texas.
In the West, the intensity of drought decreased in Utah, and moderate drought receded slightly in southern California. In the Southeast, moderate and severe drought receded in Georgia and Alabama, but drought intensified in central Florida. On the Hawaiian Islands, drought eased on Maui and Molokai but intensified on the Big Island.
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 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 U.S. Department of Agriculture, and about 350 drought observers across the country. It is released each Thursday based on data through the previous Tuesday morning.
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
National Climatic Data Center’s State of the Climate Drought Summary:
http://www.ncdc.noaa.gov/sotc/drought/
Seasonal Drought Outlook:
http://www.cpc.ncep.noaa.gov/products/expert_assessment/seasonal_drought.html
-- Kelly Helm Smith, National Drought Mitigation Center