DEXTER, Mich. (AP) - Utility crews are working to get the power back on for thousands of customers in four Midwestern states today.
      
A string of severe thunderstorms raked the region last night.
      
Sheriff's officials say a driver was killed near Dexter, Mich., about 40 miles west of Detroit, when winds toppled a tree onto a vehicle.
      
In Chicago, it blew out windows in the 110-story Willis Tower. Witnesses say the debris looked like icicles falling from the skyscraper, formerly known as Sears Tower.
      
Utility officials in Illinois, Michigan, Wisconsin and Indiana are reporting power outages.