Dangerously cold arctic air swept across a huge swath of the US on Monday, making travel treacherous, forcing schools to close and prompting officials to plead with residents to stay indoors.
A shift in a weather pattern known as the “polar vortex” triggered a drastic drop in temperatures to lows not seen in two decades and coincided with wind-chill warnings in much of the east of the country.
Comertown, Montana, recorded the lowest wind chill value so far at minus-53?C, while North Dakota, South Dakota and Minnesota were not much warmer.
That was significantly colder than the South Pole, which recorded a wind chill reading of minus-33.8?C.
Even the typically temperate Deep South was feeling the chill, with a hard-freeze warning threatening crops and livestock.
On the East Coast, a brief lull in the deep freeze greeted morning commuters, but rainstorms threatened to turn roads and sidewalks into ice rinks overnight as temperatures were expected to plunge.
The body of a 90-year-old woman was found face down in the snow next to her car in Ohio on Monday morning, the Toledo Blade reported.
At least a dozen other people were reportedly killed in crashes on icy roads, including four people whose sport utility vehicle slid off a rural Minnesota highway and fell into the Mississippi.
Four Chicago men aged 48 to 63 died of apparent heart attacks while shoveling the snow over the weekend, the Chicago Tribune reported.
The cold snap came after two massive winter storms snarled travel, grounded thousands of flights and dumped as much as 60cm of snow in the first few days of the year.
More than 4,300 US flights were canceled on Monday — nearly half of those in Chicago — and more than 6,500 were delayed, according to FlightAware.
The city of Chicago was among scores of municipalities which told parents to keep their children at home rather than risk sending them out into winds so bitter that skin could freeze in a matter of minutes.
Illinois Governor Pat Quinn declared a state of emergency and called up the US National Guard to help rescue stranded motorists as high winds whipped up blinding snow.
Quinn praised the “heroic” efforts of National Guard troops who cleared a 375-vehicle backup, and a forestry officer who rescued seven stranded people and two of their pets using a snowmobile.
In Milwaukee, Wisconsin, officials warned residents to stay indoors and urged schools to shut down as temperatures dropped to minus-24.4?C, with the wind chill making it feel like minus-38.3?C.
“Police are reaching out to homeless citizens in order to help them find the nearest shelter,” Milwaukee city spokeswoman Sarah DeRoo said.