(CHICAGO) -- Severe storms passed through the Midwest on Sunday, causing at least six fatalities and extensive damage.
At least 37 people have been injured, but that number is expected to jump significantly.
At least 50 houses have been destroyed and thousands of power outages are expected.
Storm Prediction Center meteorologist Corey Mead said some wind gusts were up to 70 miles per hour. Preliminary findings measured a tornado that struck Washington, Ill., as an EF-4 storm, uncommonly strong for November.
On Monday morning, Illinois Gov. Pat Quinn declared seven counties to be state disaster areas.
In Chicago, emergency management officials activated tornado sirens, and flights from O'Hare and Midway airports were temporarily grounded.
While the wave of storms passed through the city, the Chicago Bears home football game against the Baltimore Ravens was delayed for about two hours.
ABC's Jim Rose at Chicago's Soldier Field said, "It's raining very, very hard here right now, the winds are blowing, there's are few dark clouds."
ABC's Diane Pathieu, also at Chicago's Soldier Field, reported that fans were being told to find cover.
"They're clearing the stadium for a precautionary measure. They're ordering everybody to get to cover, to get to an interior concourse, and try and stay safe," Pathieu said.
ABC News reports that 60,000 people who were inside the stadium were evacuated to safety in shelter areas. The skies have since cleared up and the football game has resumed.
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