Chicago Fire Department Lieutenant Charley De Jesus walks around an ice-covered warehouse that caught fire on Tuesday night in Chicago on Wednesday. An Arctic blast continues to grip the US Midwest and Northeast on Wednesday, and fierce winds made some locations feel as cold as - 46 C. [Photo/Agencies]

Arctic air sweeping through Canada and parts of the United States sent temperatures plunging to record lows on Wednesday with a wind chill of -40 C.

Canada was the coldest nation in the world at the start of the day with temperatures as low as -43.1 C in the Northwest Territories, according to public broadcaster CBC.

In Ottawa, the nation's capital, buildings cracked in the cold, making sounds like the crash of a wrecking ball.

No significant damage was reported. One death was linked to the cold after a man was found dead in Toronto with signs of hypothermia.

In Rouyn, Quebec, temperatures dropped to -40.3 C, lower even than in Yakutsk, Siberia, which came in at -38.8 C.

"Low pressure in southern Canada brought a cold air mass from the north," causing a deep freeze, said meteorologist Andre Cantin of Environment Canada.

The cold snap was being felt as far south as the US states of Virginia and Ohio, where severe cold warnings pointed to risks of hypothermia and frostbite, as well as carbon monoxide poisoning from poorly ventilated heating sources.

The cold air is expected to linger until at least the end of the week, weather forecasters said.

In Ottawa, dog owners resisted taking their pets out for a morning walk, and many bureaucrats stayed at home.

US singer Miley Cyrus and her fiance actor Liam Hemsworth, wearing sweatshirts for a trek to a downtown bookstore, said they were "freezing" after just coming from Costa Rica.

Hemsworth, who starred in The Hunger Games, was in town working on a film.

Schools were closed across eastern Canada, and 5,000 homes were without electricity in Quebec province.

In Montreal and Toronto, shelters offering a bed and a hot meal quickly filled up overnight.

New York City opened scores of warming centers, where anyone can go and thaw out during daytime hours. In neighboring Connecticut, Governor Daniel Malloy urged similar measures in his state.

"Overnight temperatures over the next few days are expected to range from 0 to 10 C. Factor in the wind chill, and it will feel like 0 to -15 C," he wrote on his Facebook page.

"We are also encouraging local communities to consider opening warming centers or other facilities to help people in need," he said.

The cold was most painful in areas of New York where electric power and other infrastructure remains battered in the wake of Superstorm Sandy.

"It's cold, like we're outside, because once the generator's cut, that's it: No power, no lights, anything. No heat," said Sandra Green, a resident in the badly hit coastal Rockaways neighborhood.

"What I will do if it goes that way without the heat, I'll set the house on fire and I will stand beside it and stay warm," another resident of the devastated area said on radio.

Washington was still far from its all-time record low of -26 C set on Feb 11, 1899, the day of a severe cold spell from Maine to Florida that preceded the Great Blizzard of 1899.

But it was enough to send a shiver through the US capital two days after the public inauguration of President Barack Obama's second term - an event that saw an estimated 1 million people brave the winter chill.

By late morning the temperature in Washington had fallen to -6 C, but the wind from the northwest made it feel more like -11 C under partly sunny skies.