Drought 2009 (updated August 27, 2009)
Minnesota's present drought conditions are the result of two spells of dry weather.
Long-term dry spell: In east central 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 Moderate to Severe drought by the U.S. Drought Monitor (map at right).
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. Some Minnesota counties are categorized as being Abnormally Dry or undergoing Moderate Drought (map at right). Precipitation totals have been roughly 50% to 75% of normal since April 1, falling short of average by four to six inches (maps below).
Weekly rainfall totals through Monday morning, August 24 (map at right), exceeded one inch across most of the southeastern two-thirds of Minnesota. Heavy rains of two or more inches fell last week on portions of west central Minnesota. Very heavy rain, topping four inches in some cases, fell last week in east central Minnesota. In some of Minnesota's most drought-stricken landscapes, last week's rains, along with ample rain earlier in August, have cut away at precipitation deficits built up over the course of many months. The newest release of the U.S. Drought Monitor depicts categorical improvements in many areas compared with previous week.
Temperatures for the week were below normal, a recurring theme throughout the 2009 growing season.
- Agriculture - The Agricultural Statistics Service reports that 19 percent of Minnesota's topsoil moisture across was "Short" or "Very Short" as of August 23. This was nearly a 20 percent improvement over the previous week when 37 percent of topsoil supplies were reported as deficient.
- Stream flow - Stream discharge for many monitoring locations across Minnesota has increased substantially during August. Only a handful of measurement sites presently rank below the 25th percentile in the historical distribution for the date. The lowest flows, relative to historical data, are observed along the Upper Mississippi River above Brainerd.
- Lake and Wetland Levels - Water levels on many central and east central Minnesota lakes and wetlands are low. Recent rains have notably increased water levels in many smaller water bodies. However, for significant rises to occur in the larger water bodies, above-normal precipitation is needed throughout the late summer and in the autumn. According to the Minnehaha Creek Watershed District, discharge at Lake Minnetonka's Grays Bay Dam, the outlet to Minnehaha Creek, remains suspended per operating procedures.
- Wildfire Danger - The Department of Natural Resources - Division of Forestry classifies wildfire danger as Low throughout Minnesota.
Long-term precipitation deficit map: