Many streets and viaducts were also flooded in the Chicago area, forcing some of them to close.
Traffic was jammed on area expressways because of standing water, but they started moving again around 10 p.m. when the rain diminished.
The National Weather Service estimated rain was falling at a rate of 1.5 to 2 inches per hour at one point — up to twice the rate that can trigger flash flooding in urban areas.
There were reports of quarter inch size hail and 60 mile an hour wind gusts.
Just before 9 p.m., National Weather Service officials said about three inches of rain had fallen in the Chicago area and lightning had been spotted. The Weather Service had also issued a marine advisory for Lake Michigan and a severe thunderstorm warning for the city.
Across the region about 15,000 households were without power as of 8 p.m., ComEd spokeswoman Noelle Gaffney said.
By 6 a.m. this morning, that number was down to 3300 outages.
The Chicago Tribune contributed to this report
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