Washington  - Winter storms roared across large swathes of the United States and Canada, dumping several centimetres of snow, throwing Christmas travel plans out of gear and causing power outages Monday.

Holiday travellers were stranded in the north-eastern and north- western US, over the weekend and on Monday, after flights were delayed or cancelled and icy highways were shut down.

Anxious travellers queued up outside Seattle-Tacoma International Airport on Monday, where major carriers Alaska Airlines and Horizon Air suspended service on Sunday. Some would have to wait until mid- week or later to fly out of Seattle, CNN reported.

Portland, Oregon experienced its heaviest snowfall since 1968, with nearly 30 centimetres of snow. At least 120 flights were cancelled at Portland International Airport on Monday and drivers were advised to stay off roads.

In the northeast, flights were delayed at Newark-Liberty International Airport in New Jersey, and more than 210 kilometres of a highway in New York state was closed Monday morning after dozens of vehicles slid off the road.

Raging winds and snow storms caused power lines to collapse in the Midwest, leaving tens of thousands of homes with power in Illinois, Ohio and Indiana.

Meteorologists forecast milder weather on Christmas Eve Wednesday, with rain instead of snow in New York, Boston, Philadelphia and Washington DC and temperatures expected to climb up to 10 degrees Celsius. But fog could hamper post-holiday travel.

The winter storm also walloped Canada, which was shrouded in white from coast to coast for the first time since 1971. The town of Watson Lake in Yukon was the coldest in the country with a low of minus 45 degrees Celsius. In Vancouver, the temperature hovered at minus 15 Celsius, the coldest since the 1960s, the Globe and Mail reported.

Vancouver, which is generally without snow, was headed for its first white Christmas since 1998. (dpa)