Extreme cold gripped Canada and northern parts of the United States on Monday, prompting calls for residents to stay indoors amid increased risks of frostbite and hypothermia.

Freezing rain on top of snow over the weekend draped most of eastern Canada under a sheet of ice, making driving impossible. Minor accidents were reported all over.

Hundreds of thousands in Quebec province were without electricity overnight, but most power was to be restored by the end of the day, according to the local utility.

In Montreal and Toronto, dozens of flights were delayed or cancelled due to ice build-up and blowing snow. Chicago, Minneapolis and Buffalo airports also reported delays.

In the Great Lakes region, snowdrifts closed several roads. Snow clearing is expected to take at least two days.

Meanwhile in westernmost British Columbia province, officials warned of an increased risk of avalanches following a heavy snowfall in mountain regions.

Residents of alpine towns were urged not to travel unless absolutely necessary, and to bundle up if they went outdoors.

And the severe weather brought by an Arctic blast was forecast to continue through much of the week ahead.

In most major Canadian and northern US cities, temperatures hovered around -20 degrees Celsius (-4 F), but with a windchill felt like -45 degrees Celsius (-49 F) in some parts, according to meteorologists.

At these temperatures, exposed skin can freeze in under two minutes.