Northern Illinois and northwest Indiana were walloped by one of the most powerful winter storms in history between January 31 and February 2, 2011. An initial period of light accumulating snow occurred from the evening of January 31st into the morning of February 1st, including lake effect snowfall over northeastern Illinois.
The most memorable period of the storm occurred from the afternoon of February 1st through the early morning of February 2nd, when a powerful area of low pressure tracked slowly north. During this time, the snowstorm was accompanied by fierce winds, gusting to 50 to 60 mph, and even higher at times. The intense winds and heavy snow reduced visibility to near zero at times and produced widespread snowdrifts of 2 to 5 feet, and a few drifts of 10 feet or more.
The storm was powerful enough to generate vigorous updrafts, resulting in lightning, thunder, and small hail. Over the three day period, snowfall totaled 21.2 inches officially at Chicago’s O’Hare Airport, making it the third largest snowstorm on record for the city of Chicago. The official total at Rockford Airport was 15.1 inches, which is also third on the all-time list for Rockford.