A concentrated patch of sunlight, known as a sun dog, appears to the left and right of the sun over downtown Kalamazoo, Mich. on Thursday, Jan. 31, 2019. (Photo: AP)

A harbor light is covered by snow and ice on the Lake Michigan at 39th Street Harbor, Wednesday, Jan. 30, 2019, in Chicago. (Photo: AP)

People enjoy at the Lake Michigan at 31st Street Harbor, Wednesday, Jan. 30, 2019, in Chicago. (Photo: AP)

A firefighter walks past an ice-encrusted home after an early morning house fire Wednesday, Jan. 30, 2019 in St. Paul, Minn. (Photo: AP)

Flight information screens show flight status information at O'Hare International Airport in Chicago, Thursday, Jan. 31, 2019. (Photo: AP)

The sun rises behind trees along the shore of Lake Michigan at Montrose Harbor, Thursday, Jan. 31, 2019, in Chicago. (Photo: AP)

Fred Kuehn, owner of Lifestyle Cycle second from right, leads a group of cycling enthusiasts on a short ride to Bakers Square in Libertyville, Ill., Thursday, Jan. 31, 2019. (Photo: AP)