Drought 2009 (updated July 30, 2009)
Portions of Minnesota are in the throes of drought. Minnesota's present drought conditions are the result of two spells of dry weather.
Long-term dry spell: In east central and southeast Minnesota, a long-term episode of dryness began in mid-June of 2008 and continues to the present. Long-term precipitation deficits in these areas range from eight to fourteen inches (map below). Counties in this area are categorized as experiencing Severe Drought by the U.S. Drought Monitor (map at right). The greatest impacts of this long-term spell of dry weather are observed in east central Minnesota and extend northeast into northwestern and north central Wisconsin.
2009 growing season dry spell:
With a few dramatic exceptions, 2009 growing season precipitation has been well short of historical averages nearly everywhere in Minnesota. Many Minnesota counties are categorized as being Abnormally Dry or undergoing Moderate Drought (map at right). The area experiencing 2009 growing season precipitation shortfalls overlaps with the long-term drought area, amplifying the problem in those counties. Precipitation totals have been roughly 30% to 70% of normal since April 1, falling short of average by four to seven inches (maps below). Growing season precipitation totals for a section of west central Minnesota and portions of eastern Minnesota rank below the 2nd percentile (one year in 50) in the historical distribution.
Weekly rainfall totals through Monday morning, July 27 (map at right) exceeded one inch in many eastern, central, and northern Minnesota counties. Rainfall totals topped three inches in a narrow band from Brainerd to Moose Lake. Temperatures for the week were once again cool, averaging two to five degrees below the historical mean. The seasonally cool weather in July has led to lower than average evaporation rates and kept the drought situation from deteriorating more rapidly.
- Agriculture - The Agricultural Statistics Service reports that 43 percent of Minnesota's topsoil moisture across was "Short" or "Very Short" as of July 26. In spite of the dry conditions, relatively little of Minnesota's cropped acreage is described as being in poor or very poor condition.
- Stream flow - Stream discharge in roughly one quarter of Minnesota's rivers ranks below the 25th percentile in the historical distribution for the date. Last week's rains increased stream flow in many central and northeastern Minnesota watersheds.
- Lake and Wetland Levels - Water levels on many east central Minnesota lakes and wetlands are quite low. The White Bear Lake Conservation District reports that White Bear Lake was within six inches of its all-time record low level as of mid-July. Lake Minnetonka level has declined to its lowest value since early 2001. According to the Minnehaha Creek Watershed District, discharge at Grays Bay Dam, the outlet to Minnehaha Creek, has been suspended per operating procedures.
- Wildfire Danger - The Department of Natural Resources - Division of Forestry classifies wildfire danger as Low over much of Minnesota. A few northern Minnesota counties and the Twin Cities metropolitan area report Moderate fire danger.
Long-term deficit map: