State of emergencies have been declared in Chicago, Wisconsin and Michigan as some of the coldest weather in a generation descended upon the US midwest. The brutal chill has been caused by a polar vortex, a band of arctic freezing air which has made its way south. Temperatures have plummeted to life-threatening sub-zero levels of minus 40F (-40C) in some states.
The current record for the coldest temperature in Chicago is -33C (-27F).
Today, the mercury dropped to -31C (-24F) in the west of the city at 5am local time.
But the National Weather Service Chicago said that record looks likely to be broken tomorrow.
NWS Chicago tweeted: “Last day of the bitter cold, Thurs, will likely start with some all-time record cold.
“Early AM lows will be in -20s to -30s across the area. Isol’d readings of around -40° psbl west of Fox Valley.
“Lighter winds but still dangerous cold to be in if not dressed for it.”
NBC Storm Team 5 meteorologist Andy Avalos also warned “tomorrow morning has the potential to be even colder than this morning”.
The weather forecaster said: “The good news is the winds will be dying down considerably so the wind chill values will not be as deadly in the -30F to 40F category.
“But the actual temperatures will probably be colder, -22F (-30C)here in the city, -30F (-34C) to -32F (-35) in the colder spots.
“The coldest temperature ever recorded in Chicago is 27 below 0, I’m going to go with 26 so we are going to be very close with that.”
He added there would be “little recovery” throughout the day with temperatures climbing to -4F (-20C) at Chicago O’Hare airport by 4pm local time.
Although temperatures will then start to recover, the next threat after the “horrible temperatures” will be “accumulating snow” arriving by 7pm local time
Up four inches of snow could fall in Chicago by the end of the night.
This spells further bad news for Chicago’s hard-hit travel network.
More than 1,800 flights were cancelled at the city’s two international airports, O’Hare and Midway, amid the deep freeze.
Amtrak also halted all of its train services, while hundreds of schools were closed.
Official warming centres have opened across the city and five city buses were turned into temporary shelters for homeless people.