WeatherWhys for January 31,2014 from accuweather.com

Three years ago, the Groundhog Day Storm tracked from the Plains, across the Midwest and to New England. The storm evolved into an all-out blizzard across the southern Great Lakes. Chicago was brought to a virtual standstill as 21.2 inches of snow buried the city. Wind gusts in excess of 55 to 70 mph severely blew and drifted the snow around. The 13.6 inches of snow that fell alone on Feb. 1, 2011, remains Chicago's snowiest February calendar day.