Figure 1. Trees snapped off along the Chicago lakefront by winds from the Blizzard of 2011. Image credit: viewer uploaded photo from WGN.

Revisiting the Chicago blizzard
This week's blizzard in Chicago dropped 20.2" of snow on the city, Chicago's third-greatest snowstorm on record. But the tremendous winds that accompanied the blizzard--gusting to 61 mph at O'Hare Airport, and 70 mph at the Lakefront--made the storm Chicago's worst-ever blizzard as far as impacts on travel. Another remarkable feature of the storm were the intense thunderstorms that developed. According to an excellent write-up on the storm posted by the Chicago National Weather Service office, the Blizzard of 2011 had 63 lightning strikes, and several reports of hail. The most extraordinary hourly observation I've ever seen in a U.S. winter storm came at 9:51pm on February 1 at Chicago's Midway Field: A heavy thunderstorm with lightning, heavy snow, small hail or ice pellets, freezing fog, blowing snow, visibility 300 feet, a wind gust of 56 mph, and a temperature of 21°F. Welcome to the Midwest! Thanks go to meteorologist Steve Gregory for pointing this observation out to me.


Figure 2. Snow amounts from the February 1 - 3 blizzard of 2011 peaked at over 2 feet along the shore of Lake Michigan between Chicago and Milwaukee. Strong northeasterly winds pulled moist air off of the Lake in this region, allowing the "lake effect" to enhance the blizzard's snows in this region. Image credit: Chicago National Weather Service office.

Jeff Masters