Thick snow is blanketing the north-eastern US and eastern Canada as a major storm cuts power to thousands of homes and plays havoc with transport.
Massachusetts, Rhode Island, New York, Connecticut and Maine are all on an emergency footing, with millions of residents being warned to stay indoors.
Massachusetts Governor Deval Patrick has temporarily banned all non-essential traffic on the state's roads.
Meteorologists say the storm could be New England's worst for decades.
Airlines cancelled more than 4,300 flights - including all those to and from the three major airports in New York City - and the train operator Amtrak has suspended nearly all services north of the city.
People have been warned to stay off the roads, and stock up on food and other supplies as the storm affects 25 million people in the region.
More than 330,000 power cuts have been reported in Massachusetts, Rhode Island and Connecticut.
A nuclear power station in Massachusetts also lost power and was forced to shut down. Back-up generators are operating equipment and there is no threat to the public, officials said.
Canadians on the Atlantic Coast are also bracing for blizzards after heavy snow fell on Ontario.
New Brunswick, Nova Scotia and Newfoundland are under blizzard or storm watches.
Ontario has already seen 200 vehicle accidents, the CBC reported. At least three people have been killed.
One US man in his 70s also died when he lost control of his vehicle in Poughkeepsie, New York.