Brace for the Big Chill — now, it’s our turn.

Life-threatening cold locked much of North America in its icy grip Sunday, lashing the U.S. Midwest and Canadian prairies with some of its most severe weather in two decades and packing dangerous wind chills as low as — 50 C.

The record-shattering cold, produced by the same Arctic air mass, is expected to blast Southwestern Ontario Monday night, creating extremely dangerous conditions with a wind chill of – 40 C.

Warnings flew Sunday about limiting exposure to the cold and cancelling unnecessary travel.

In London, forecasters are calling for temperatures to plunge as low as — 28, three times colder than what the region typically gets this time of year.

“In just a couple of minutes you would be starting to have a risk of frostbite,” warned Environment Canada’s Arnold Ashton on Sunday. “It’s pretty extreme.”

For the record, Monday’s outlook for London is colder than such deep freeze zones as Iqaluit and Edmonton, and will rival the temperature in Winnipeg where it was so cold one day last week ( — 48, with the wind chill) the Manitoba capital was colder than a crater on Mars.

While Monday’s forecast high for London is expected to reach — 8, the temperature will struggle to get out of the deep freeze Tuesday, with both the high and low only a few degrees apart near — 20.

What worries Ashton is that winds could escalate to 60 km/h or more, creating wind chills of – 40 C and possibly lower.

In weather that cold, frostbite can set in on uncovered skin in minutes, experts warn.

“It’s probably the coldest air we have seen in years in the region,” said Ashton.

“We’re looking at very severe conditions,” he said.

Coming off heavy snow Sunday night, the brutal cold could create hiccups for many workers and school children getting back to normal after the extended holiday break.

If forecasters are right, the record London low of – 25 for Jan. 6 set in 1970 could be shattered.

Along with the cold, intense snow squalls are expected to develop southeast of Lake Huron and Georgian Bay, with 10 to 15 cm forecast over a large area.

Environment Canada warned travel conditions will become extremely hazardous because of blowing snow. The blizzard-like conditions, and extreme wind chills, could be “potentially life-threatening” for drivers stranded on snow-blocked highways, the agency said in a special weather statement.

“Travellers need to ensure they have an adequate car emergency kit and ample fuel if travelling any distance,” the agency said.

In London, temperatures are forecast to climb to a more balmy – 13 Wednesday and zero by Saturday.

That’s still a long way from this time last January, when London basked in highs up to 11.

john.miner@sunmedia.ca

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PROTECT YOURSELF

Stay indoors

Wear multiple layers outdoors

Cover exposed skin

Drink warm fluids; avoid caffeinated or alcoholic beverages

Avoid strenuous exercise

Source: Middlesex-London Health Unit

BY THE NUMBERS

28C: London’s forecast low Monday

40C: Wind chill factor

9C: Average low this time of year

25C: Record low Jan. 6, set in 1970