A monthly electronic newsletter summarizing Minnesota climate conditions and the resulting impact on water resources.

Distributed on the Wednesday following the first Monday of each month.

State Climatology Office - DNR Waters

compiled 1/5/01 (delayed distribution)

- December precipitation was above normal across southeastern and south central Minnesota, below normal in northeastern Minnesota, and near normal elsewhere. December precipitation totals topped two and one half inches in south central and southeastern Minnesota, exceeding long-term December averages by more than an inch in some places.

(see: http://climate.umn.edu/cawap/monsum/monsum.asp )

(see: http://climate.umn.edu/cawap/monsum/monsum.asp )

- frequent and sometimes heavy snow events led to a significant snow cover across most of Minnesota by the end of December. By month's end, nearly all of Minnesota reported over 8 inches of snow on the ground, and in many locations, over 12 inches. Snow depths in the southwestern two thirds of Minnesota rank above the 80th percentile for the date.

(see: http://climate.umn.edu/doc/snowmap.htm )

(see: http://enso.unl.edu/monitor/monitor.html )

- the December 30 Palmer Drought Severity Index (PDSI) depicts most of Minnesota in the "Near Normal" category. Counties in northwestern and north central Minnesota are categorized as experiencing an "Unusual Moist Spell". The Palmer Drought Severity Index is used for assessing long-term meteorological conditions.

(see: http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/regional_monitoring/palmer.gif )

- stream discharge values are difficult to determine during the frozen water season. However, for gauging locations that provide winter data, the U.S. Geological Survey indicates that most streams in the Red River basin are above the 90th percentile when compared to historical values for the date. Stream flows in the remainder of the state are near average for the date.

(see: http://water.usgs.gov/cgi-bin/daily_flow?mn )

- cold temperatures in December led to rapid lake and river ice development. Lake and river ice is the thickest in four years.

- frost depths across the state range from 8 to 20 inches in areas with adequate snow cover. In those areas blown free of snow cover, frost depths are much deeper.

(see: http://www.mvp-wc.usace.army.mil/bulletins/Snow_Ice_Frost.html

(see: http://www.cpc.ncep.noaa.gov/products/predictions/multi_season/13_seasonal_outlooks/color/seasonal_forecast.html )

(see: http://www.cpc.ncep.noaa.gov/products/predictions/multi_season/13_seasonal_outlooks/color/seasonal_forecast.html )

- (repeated from last month) ... although  historical precipitation averages drop off significantly during November, central and east central Minnesota overcame the probabilities and received relief in the form of very heavy rains. The rains came before the first significant cold spell of the winter season, thus soils were unfrozen and receptive to recharge. While the rains have done much to alleviate hydrological imbalances in these areas, adequate spring snow-melt runoff and early spring rains are still necessary to fully rejuvenate wetland, lake, and stream levels in 2001.

Conversely, soil moisture and surface water systems are at unusually high levels in northwestern Minnesota, and above average spring snow-melt runoff or above average early spring rains could pose problems in the spring of 2001.

Contributions of information and suggestions are welcome!