Drought 2009 (updated October 1, 2009)
Minnesota's present drought conditions are the result of two spells of dry weather.
2009 growing season dry spell:
With a very few exceptions, 2009 growing season precipitation has been well short of historical averages across Minnesota. As a result, many Minnesota counties are categorized as being Abnormally Dry or undergoing Moderate to Severe drought (map at right). Precipitation totals have been roughly 50% to 75% of normal since April 1, falling short of average by five or more inches (maps below).
2008-2009 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 at bottom of page). Counties in this area are categorized as experiencing Severe to Extreme drought by the U.S. Drought Monitor (map at right).
Weekly rainfall totals through Monday morning, September 28 (map at right) ranged from one and one-half inches to three inches over portions of southwest Minnesota. Much of the southern one half of the state received at least one-half inch of rain. Heavier rains were also reported along the Canadian border. Elsewhere in northern Minnesota, rainfall totals were generally less than one-third inch. Rainfall totals for September are short of historical averages by one to three inches over much of eastern Minnesota.
Temperatures for the fourth week of September were once again well above normal across Minnesota. September 2009 will go into the record books as one of Minnesota's warmest Septembers ever. Warm temperatures enhance evaporation and transpiration rates, worsening the drought situation.
- Agriculture - The Agricultural Statistics Service reports that topsoil moisture is "Short" or "Very Short" across 40 percent of Minnesota's landscape as of September 27.
- Stream flow - Stream discharge values for roughly one-quarter of Minnesota measurement sites rank below the 25th percentile in the historical data distribution for the date. Many measurements fall below the 10th percentile when compared with historical late-September values. Some of the lowest flows, relative to historical data, are observed along the Mississippi River and the Upper St. Croix River.
- Lake and Wetland Levels - Water levels on many central and east central Minnesota lakes and wetlands are very low. The White Bear Lake Conservation District reports that White Bear Lake is within three inches of its all-time recorded low level. 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. The Prior Lake-Spring Lake Watershed District indicates that Prior Lake water levels are the lowest since the early 1990s. For significant rises to occur in the larger water bodies, above-normal precipitation is needed throughout the autumn and into 2010.
- Wildfire Danger - The Department of Natural Resources - Division of Forestry classifies wildfire danger as High in Lake of the Woods County and portions of Koochiching County. Fire danger is Moderate in many northern and eastern Minnesota counties. Elsewhere, fire danger is considered Low.
2009 growing season precipitation deficit maps: