Tornado warning sirens blared in Illinois and Indiana, and all flights were stopped by late morning at Chicago's two major airports. There were numerous reports of wind gusts of 80 mph or more at personal weather stations, with trees blown down.
“These are dangerous storms!” the National Weather Service said by late morning.
More than 575,000 customers lost electricity in Illinois and Indiana, according to poweroutage.us. Lake County, Indiana, was especially hit hard.