Midwest Weekly Highlights - December 8-14, 2010

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Midwest Blizzard

On December 11th and 12th the Midwest was hit with a blizzard. Blizzard and winter storm warnings were issued for parts of Minnesota, Wisconsin, Iowa, Missouri, Illinois, Indiana, and Michigan (Figure 1). Low pressure moved from Montana to western Iowa and then headed east across the upper Midwest. Strong pressure gradients, especially to the north and west of the low, caused high winds which whipped up the snow severely reducing visibility (Figure 2). Snowfall totals ranged to nearly two feet in southeast Minnesota and west-central Wisconsin (Figure 3). Wind gusts exceeded 50 miles per hour and temperatures dropped to sub-zero readings behind the system. There were almost 400 record daily snowfall records set during the week with dozens recorded in each of the nine Midwest states. Thirty-two stations, in seven states, recorded their snowiest December day and 14 reported their all-time snowiest day. The days following the passage of the storm brought cold winds across the Great Lakes causing lake-effect snows downwind of the lakes. Midwest snow depths ranged up to two feet by the end of the week and drifts of six to eight feet were widespread.

More than a dozen deaths were blamed on the storm. Several fatalities were in automobile accidents. Additional deaths included a man shoveling his driveway who was struck by a plow, a man who froze trying to walk home after his vehicle got stuck, and a man crushed when a shed collapsed under the weight of the snow.

Travel was disrupted across the region. Airports delayed or cancelled hundreds of flights, particularly hard hit were Minneapolis and Chicago. Amtrak and freight trains schedules were interrupted for days with Amtrak service from Chicago to the northwest down for two days. Interstate highways were closed in several states. I-90 in Minnesota was closed from Albert Lea to the South Dakota state line, 140 miles of I-94 were closed in west central Wisconsin, both I-80 and I-29 were closed in western Iowa along with numerous other highways in the area, a 24-car accident closed I-80 in northern Illinois, and I-55 and I-57 in central Illinois were also briefly closed due to blowing snow and numerous accidents. Plows were pulled off the roads in many locations as drivers' hours mounted and conditions became unsafe to operate the plows. Some rescue crews were also shut down and only responded in cases with injuries due to the danger in deploying the crews. Table Rock Lake in southern Missouri was also affected when a boat carrying more than 600 people was blown ashore. Because of the continuing wind and waves it was decided to wait until morning before attempting to get the boat back to its dock. The boat had sufficient shelter and food to keep everyone safe for the night.

The Minnesota Vikings were inconvenienced repeatedly by the storm. First the storm rerouted their opponent's flight to Kansas City which pushed the game back a day from its scheduled Sunday kickoff. Then early Sunday morning the roof of the Metrodome collapsed, dropping snow on the field and tearing some roof panels. This caused the game to be moved to Detroit's Ford Field. Roof repairs will not be complete before the next game so the Vikings are renting out the University of Minnesota's stadium. A lot of snow removal and heating upgrades will need to be completed to prepare the outdoor stadium which had been shut down for the winter and was not designed to operate in the single digit temperatures expected at game time.

 
Precipitation

Precipitation totals were generally above normal for the northern half of the region and below normal for the southern half (Figure 4). Parts of southern Minnesota into west central Wisconsin received more than five times their normal precipitation for the week. No precipitation fell in extreme northwest Minnesota and extreme southwest Missouri (Figure 5). Daily precipitation records were set during the week with most occurring on the 12th.
 

Cold Temperatures

Cold temperatures gripped the region, ranging from daily averages near zero in northern Minnesota to near freezing in southwest Missouri (Figure 6). The entire region was at least 5°F below normal with southern Kentucky nearly 15°F below normal (Figure 7). Single digit maximum temperatures spread from Minnesota into Wisconsin and Iowa on the 13th and 14th (Figure 8). Minimum temperatures on the 14th dropped to the -20s in Minnesota and Wisconsin (Figure 9). Daily temperature records for the week were exclusively record lows .
 

-MST-