In the autumn of 2010, Cook County and portions of Lake County were designated as undergoing Moderate drought. Precipitation totals from mid-March were less than eighteen inches for sections of northeastern Minnesota, more than four inches short of average (maps below). In many of these areas, mid-March through early November precipitation totals rank below the 10th percentile (one year in ten) when compared with past years over the same seasonal interval.
Other areas in northeastern Minnesota were considered to be Abnormally Dry. Much of this region experienced growing season precipitation shortfalls in 2009 and lower than average snowfall this past winter.
Although the U.S. Drought Monitor in the Fall of 2010 no longer indicated drought in east central Minnesota, some hydrologic systems in this area remain impacted by long-term dryness that began in June of 2008. This long-term precipitation anomaly is responsible for low water levels in larger lakes and wetland complexes across Anoka, Ramsey, Chisago, and Washington counties.
The very dry weather has led to stream discharge values in northeastern Minnesota that rank below the 10th percentile when compared with historical data for the date. Lake Superior water level in fall 2010 was seven inches below fall 2009's level and 13 inches below the historical average.