Millions of Americans braced Tuesday for a dangerous polar vortex which began to settle over a large swath of the United States, threatening to set new records as schools and businesses closed and authorities warned of frostbite.
Temperatures in almost a dozen states stretching over 1,200 miles from the Dakotas to Ohio were forecast to be the coldest in a generation, if not on record.
The National Weather Service (NWS) forecast temperatures between -10 to -40 degrees Fahrenheit (-23 to -40 Celsius) by Wednesday, with the wind chill making it seem as cold as -65 degrees Fahrenheit in one area of Minnesota.
The culprit was a lobe of arctic air broken away from the polar vortex that usually encircles the North Pole.
“A record cold air mass will continue into the central and northern US, spreading to the east coast on Tuesday,” the NWS said.
“Wind chills of -30 to -60 (Fahrenheit) can be expected over portions of the northern Plains and Great Lakes region.”
Michigan and Wisconsin declared statewide emergencies in advance of the frigid temperatures.
Americans were heeding warnings to stay home if possible on Wednesday when temperatures were expected to be at their coldest.
Scores of schools, businesses and government agencies announced closures in multiple states.
“People exposed to extreme cold are susceptible to frostbite in a matter of minutes,” warned the NWS. “Areas most prone to frostbite are uncovered skin and the extremities, such as hands and feet.”
More than 70 warming centres were opened in Chicago, America’s third city where temperatures were forecast to rival or overcome the record of potentially -27 degrees Fahrenheit.
Wind chill would make the air feel closer to -40 to -50 degrees in the windy city, officials said.
Meanwhile, the northeast and parts of the south were contending with a snow storm, which had previously dumped up to a foot of snow (30 centimetres) in the Midwest over the weekend.
“Not only is brutal cold invading the central parts of the country, accumulating snow and freezing roadways all the way into the deep south could make travel dangerous,” the NWS said.
The snow was expected to make the arctic air feel even colder, the effects of which had already arrived in Canada.
The frigid cold blanketing much of the US’s northern neighbour, from Manitoba in the western Prairies region to Atlantic Canada, prompted a rare “hazardous” cold warning from Environment Canada.