According to statistics compiled by NOAA’s Storm Prediction Center, so far in 2011 Illinois has had 58 reports of tornadoes, 298 reports of significant hail (1 inch or more), and 674 reports of wind damage. That’s about average for us. Fortunately, we escaped the worst of the 2011 season that centered on the southeastern U.S. and Joplin, MO.
See the first figure below for the distribution of events. In some cases, we may have multiple tornado reports from the same tornado as it travels along.
The second figure shows the distribution of severe weather reports by month for Illinois. After a quiet start to 2011, severe weather activity picked up in April and continued through July before tapering off in August and September. You can see the monthly raw data and chart in Google Docs.
The severe thunderstorms that swept though Chicago on July 11, 2011, caused widespread damage. Here are the maps and initial reports of damages from the NOAA Storm Prediction Center. The wind damage was common throughout Chicago, as well as parts of southeastern Wisconsin, Indiana, and Michigan.
Some parts of the Chicago area received up to 0.75 inches of rain from this event, according to the reports from the Community Collaborative Rain, Hail, and Snow network (CoCoRaHS). See last map below.