Published Jan 30, 2019 at 11:52 AM | Updated at 4:16 PM EST on Jan 31, 2019
A deep freeze swept over Minnesota to Michigan, closing schools, canceling flights and halting mail delivery as people were urged to stay indoors and away from sub-zero wind chills. The mercury is expected to dip to minus 20 degrees in Chicago and elsewhere, with some places expected to see a wind chill of up to minus 60.
