An unusual bout of warm winter weather turned snow into freezing rain on Monday in western Canada, coating much of Manitoba and Saskatchewan provinces in ice, snapping power lines and stopping travel.

Federal police described the storm as one of the worst to strike the region in decades, with hundreds of vehicles sliding off slick roads.

"We've had emergency vehicles in the ditch, we had a fire truck in the ditch, and even one of the highway sanders was in the ditch," Corporal Larry Dahlman of the Royal Canadian Mounted Police (RCMP) told public broadcaster CBC.

"It basically looks like a used car lot."

No injuries were reported.

The RCMP closed a major highway between the two provinces, and another between Winnipeg and the US border, and they warned drivers to stay home for fear police or ambulances may not be able to reach them in an accident.

Most schools were also closed and several towns reported power outages.

The "extreme freezing rain" caused dozens of flights at the Winnipeg international airport to be cancelled or delayed. "We had to use tugs to push and pull aircraft off taxiways," spokeswoman Christine Alongi said.

City crews also abandoned most outdoor jobs because they could not get a foothold on icy footpaths.

According to Environment Canada, temperatures in the region are usually below minus 10 to 20 degrees Celsius in February, but were instead hovering around freezing.

Meteorologist Bob Cormier blamed two warm fronts from the Pacific Ocean and Colorado colliding over Canada's vast western plains as they tracked eastward.

"It's very unusual," he told AFP. "Usually when we get freezing rain it's limited to an hour or two, and ahead of a snowstorm. But this was prolonged."

"On average, we're seeing warmer winters and we can expect a higher probability of more freezing rain in the Prairies," he added, noting "the bulk of global warming in Canada is being felt in the Prairies region and the North".