By early-winter 2011, nearly all Minnesota counties were designated as undergoing Moderate to Severe drought. In north central and northeast Minnesota, stream flow and lake levels were very low due to the lingering impact of precipitation deficits during the 2010 growing season and spotty rainfall in 2011. Much of the southern one-third of Minnesota was rated in the Severe drought category. In those areas, significant late-summer and autumn precipitation shortfalls led to rapidly deteriorating hydrologic conditions. Precipitation totals for the eighteen-week period from late July through late November were less than three inches in many areas, a negative departure from the long-term average of five to nine inches (maps below). When compared with the same eighteen-week period in the historical database, the 2011 precipitation totals rank among the lowest on record.
Similar patterns were evident when looking at precipitation data for only the meteorological autumn (September through November) (maps below). A significant portion of Minnesota reported autumn precipitation deficits of five or more inches. For a large section of the southern one-third of Minnesota, Autumn 2011 was the driest on record.