Each season in 2011 had a memorable weather event, some with negative impacts. There were two good snow storms in February. The Groundhog Day blizzard had wind gusts of up to 60 mph and snowfall depths ranging from 1 to 2 feet. That resulted in snow drifts of 6 to 10 feet. The second storm occurred on February 20-21 with snow accumulations between 8 and 15 inches. Freezing rain and sleet also fell across southern Wisconsin.
There were 38 documented tornadoes, making the year the third busiest on record. A record-breaking tornado event occurred on April 10 with at least 15 tornadoes, including four strong tornadoes. This was the largest total number of tornadoes in one April day. There were 11 confirmed tornadoes on May 22.
Summer weather included straight line winds and a heat wave. The heat wave of July 17-21 covered most of the state with heat indices of 100 degrees to 117 degrees. A tornado-water spout was observed over Lake Mendota on August 8. Waterspouts were also observed east of Milwaukee Harbor on Sept. 24. A severe thunderstorm hit western Waukesha County on June 21 with 100+ mph winds, which leveled or damaged thousands of trees.
Labor Day saw relatively cool temperatures with lows in the 30s. Throughout October, November and December, Wisconsin experienced temperatures that were above our 30-year climatic mean.
During the year, 10 people were directly killed by weather events: one person from a blizzard, one from lightning, one from a tornado, one from non-tornadic thunderstorm winds, one from flooding and five during the July heat wave.