CHICAGO • A blast of Arctic air from the polar vortex brought dangerous, bone-chilling cold to a wide swathe of the United States, stretching from the Dakotas through Maine, with snow expected as far south as Alabama and Georgia.
The Midwest was the hardest-hit region, as temperatures plunged below minus 18 deg C on Tuesday. By nightfall, the mercury was hovering at minus 18 deg C in Chicago, minus 14 deg C in Detroit and minus 29 deg C in Minneapolis.
Local television pictures showed the Chicago River and Lake Michigan filled with chunks of ice.
The brutal blast known as the polar vortex is a stream of cold air that spins around the stratosphere over the North Pole, but whose current has been disrupted and is now pushing south into the US.
Officials warned Chicago residents, accustomed to chilling winters, to expect an unusually deep and dangerous freeze. Even the city's supply of its signature deep-dish pizza was affected: The Lou Malnati's chain stopped taking delivery orders at 8pm on Tuesday.
"This could possibly be history-making," said Mr Ricky Castro, a National Weather Service meteorologist in Romeoville, Illinois.
As much as 60cm of snow was forecast in Wisconsin, and 15cm in Illinois. Snow was expected to fall until at least yesterday from the Great Lakes region to New England.
Some Chicago residents found warmth inside the Harold Washington Library Centre.
Mr Gilbert Rothschild, the president of a liquor retailer, walked through a corridor wearing three sweaters and an undershirt underneath his parka. "The more layers, the more you're insulated", the 79-year-old said.
Many Midwest cities opened warming shelters. Regional governments closed hundreds of schools and airlines cancelled more than 2,000 flights, according to the Flightaware flight tracking website. Many had been destined for Atlanta, where the National Football League's Super Bowl will take place on Sunday.
Ms Amy Patterson, a vice-president at the Atlanta Super Bowl Host Committee, said there would still be time for fans to fly to Atlanta for the game, with the National Weather Service (NWS) forecasting a high of a balmy 14 deg C on Sunday.
A low of minus 23 deg C was forecast in Chicago and elsewhere in northern Illinois yesterday. But with the wind chill factored in, temperatures would feel as low as minus 46 deg C until today, the NWS reported.
Temperatures were forecast to reach lows of minus 34 deg C to minus 40 deg C in parts of the Northern Plains and Great Lakes yesterday, the NWS said.
The freezing weather may have killed a man in Rochester, Minnesota, who was found dead outside his home on Sunday, according to a report by WCCO radio station.
In Chicago, classes were expected to be cancelled for all 360,000 students yesterday. Detroit also said all public schools would close, and Michigan State University said it would suspend classes.
According to the NWS, the coldest recorded temperature in Chicago was minus 33 deg C on Jan 20, 1985.