The painfully cold weather holding much of the Midwest in a historic deep freeze sent temperatures plunging to record lows Thursday in several cities as the system marched eastward. But a dramatic swing of as much as 80 degrees was expected within days.
The frigid conditions canceled more commercial flights, and the number of deaths blamed on the cold climbed to 13. Yet there were signs that life was getting back to normal as some students returned to school, train travel resumed and businesses reopened.
A rapid thaw seemed imminent. For instance, Moline, Ill., saw a temperature of minus-33 degrees Thursday and was forecast to hit 49 degrees by Monday, a difference of 82 degrees.
Meanwhile, the extreme cold was settling in over the Northeast. In western New York, a storm that dumped up to 20 inches of snow gave way to subzero temperatures and dangerous wind chills. The arctic conditions caused problems from Buffalo to Brooklyn, where about 200 firefighters battling an early morning blaze in a commercial building took turns getting warm on buses.
New York Gov. Andrew Cuomo said state police would crack down on truckers who violated a travel ban issued for Interstate 90 between Rochester and the Pennsylvania border after a tractor-trailer crash was blamed for a major pileup.
Schools in parts of Wisconsin, Minnesota, Michigan, Illinois and Iowa remained closed Thursday. But students headed back to school in eastern North Dakota, where subzero temperatures were forecast to crawl upward.
The blast of polar air also strained infrastructure with some of the lowest temperatures in a generation, snapping rail lines and knocking out utilities. In Detroit, more than two dozen water mains froze. About 1,700 flights in and out of Chicago airports were canceled.
Chicago's temperature dropped to a low of around minus-21 degrees on Thursday, slightly above the city's lowest-ever reading of minus-27 in January 1985. Milwaukee's low was minus-25 and Minneapolis recorded minus-24 with wind chills as low as minus-38, an improvement from a day earlier.
Rockford, Ill., saw a record low temperature of minus-31 on Thursday. Cedar Rapids, Iowa, set a record low of minus-30.
Towing companies saw a huge demand for service after hundreds of vehicles got stranded. Trains and buses in Chicago operated with few passengers.
The hardiest commuters ventured out only after covering nearly every square inch of flesh against the extreme chill, which froze ice crystals on eyelashes and eyebrows in minutes. The Postal Service even took the rare step of suspending mail delivery in many places, and United Parcel Service also halted deliveries in several areas.
The bitter cold was the result of a split in the polar vortex, a mass of cold air that normally stays bottled up in the Arctic. The split allowed the air to spill much farther south than usual.
The weather-related deaths included an elderly Illinois man who was found several hours after he fell trying to get into his home, an Ohio woman found in a vacant home, and a University of Iowa student found dead behind an academic hall.
In Michigan, state and utility officials warned residents that they risked brief interruptions of natural gas service if they did not help reduce energy. The warning followed a fire at a utility's suburban Detroit facility that affected natural gas supplies. By Thursday, Consumers Energy said it was "cautiously optimistic" that its requests to curb natural gas use were "having a positive effect."
Amtrak began to restore service out of Chicago, one of the nation's busiest rail hubs, after canceling dozens of trains.
In Saco, Maine, firefighters battling a blaze had to worry about frostbite, slippery conditions and frozen gear as they chipped away at ice and snow to move hoses. A siren got stuck, contributing to the bedlam. Firefighters took breaks to warm up, but the conditions wore them down.
"You could see the look on their faces. They were cold," Deputy Fire Chief David Pendleton said.