HydroClim Minnesota - January 2012

A monthly electronic newsletter summarizing Minnesota's climate conditions and the resulting impact on water resources. Distributed on the Wednesday following the first Monday of each month.

State Climatology Office - DNR Division of Ecological and Water Resources, St. Paul
distributed: January 4, 2012

What happened in December 2011:

• December 2011 was yet another dry month across much of Minnesota. In many counties, it was the fifth consecutive month of precipitation shortfalls. Some drought-stricken counties in southern Minnesota received near-normal precipitation in December. However, this welcome precipitation did not by any means mitigate the very large moisture deficits built up during the late summer and autumn.
• Monthly mean temperatures for December 2011 were very warm, topping the historical average by six to twelve degrees across Minnesota. Preliminary data indicate that December 2011 will rank among the warmest Decembers in the historical record. It was the third consecutive month of abnormally warm temperatures. The final quarter of 2011 was the warmest October through December period in 80 years. Extreme temperature values for December ranged from a high of 60 degrees F at Madison (Lac Qui Parle County) and Milan (Chippewa County) on the 19th, to a low of -17 degrees F at Brimson (St. Louis County) and Babbitt (St. Louis County) on the 6th. Maximum temperature records were set at numerous locations on December 18, 24, and 26.

Where we stand now:

• The U. S. Drought Monitor, released on December 29, depicts every Minnesota county as experiencing some level of drought. Large sections of northern Minnesota are said to be undergoing Severe Drought or Moderate Drought. Stream flow and lake levels in those areas are very low due to the ongoing impact of precipitation deficits accrued during the 2010 growing season and spotty rainfall this past warm season. The Drought Monitor also places much of southern Minnesota in the Severe Drought or Moderate Drought categories. Precipitation totals since late-summer have been far below historical averages across the southern one-third of Minnesota. The U. S. Drought Monitor index is a blend of science and subjectivity where drought categories (Moderate, Severe, etc) are based on several indicators.
• The present snow depth is well below the historical median in nearly every Minnesota county. Northeast Minnesota communities report four to eight inches of snow cover as of this writing. The snow is eight to 12 inches deep in the Lake Superior Highlands of Lake and Cook counties. A narrow stripe of three to six inch snow depths extend from Grand Forks to Bemidji. Elsewhere in Minnesota, snow depths are generally one to three inches, with many locations reporting a snow-free landscape.
• The U.S. Geological Survey reports that stream discharge values (where winter monitoring is possible) are very low in northeast and north central Minnesota watersheds. Stream flow values rank below the 10th percentile for this time of year for a number of rivers in the northern tier of Minnesota counties. Stream flow measurements are also low for a few south central Minnesota watersheds. For the Red River and some of its tributaries, river flow is high when compared with historical data for the date, the lingering impact of a wet autumn 2010 and spring 2011.
• The Lake Superior water level is near its elevation of a year ago, but down 14 inches from the long-term seasonal average. Water levels on many Minnesota lakes are low when compared with historical averages.
• In their final report of the season (November 7), the Minnesota Agricultural Statistics Service reported that topsoil moisture was 28% Very Short, 43% Short, 29% Adequate, and 0% Surplus across the state. Dry soils made autumn tillage very difficult in many areas and heightened concerns about the soil moisture profile for next growing season. Late-autumn conditions act as a predictor of the soil moisture situation entering the 2012 growing season.
• The soil is frozen four to eight inches deep in southern Minnesota and 12 to 24 inches deep in northern Minnesota.
• Some Minnesota lakes are only partially ice covered. Open water on Minnesota's lakes in early January is rare. Ice conditions are highly variable. Lake and river ice is NEVER completely safe for walking or driving.
• The potential for wildfires is currently rated by DNR Forestry as Low across Minnesota. It is unusual to discuss wildfire danger in January. However, burning

From the author:

• Without ample, widespread precipitation in the late winter and early spring, Minnesota will face a number of drought-related issues at the beginning of the 2012 growing season. Other than the scarcity of snow cover, Minnesota's drought presently exhibits relatively few observable negative impacts. The drought situation will become rapidly apparent in the spring in the form of deficient soil moisture supplies and low water levels in wetlands, lakes, and rivers.