Meterologists are calling hurricane-like weather in the Midwest one of the worst storms to hit the region in decades.
Severe thunderstorms, hurricane-force winds, and heavy rains battered states from Arkansas to Ohio, Tuesday.
The storm -- nicknamed a "chiclone" and "windpocalypse" -- knocked down trees, damaged homes, and took down power lines. Tens of thousands are without electricity.
"This is a very different type of event," said Edward Fenelon, a National Weather Service meteorologist in Romeoville, Ill. "But that does give an indication of the magnitude of the winds. This isn't something you see even every year."
In St. Louis, strong winds were blamed for a partial building collapse that sent bricks, mortar, roofing, and some window air conditioning units raining down onto a sidewalk.
Flights were also delayed at Chicago's O'Hare International Airport, a major hub for American and United airlines.
Sustained winds of 35 to 40 mph and gusts up to 60 mph were expected in the region throughout the afternoon, the National Weather Service said.