A vicious Arctic wind blew across the north east of the United States last night, killing six people and leaving New York city with its coldest overnight temperatures since records began in 1893.

With temperatures as low as -40C (-40F) in some areas the New York police department scoured the streets, rounding up homeless people and taking them to shelters.

"Any exposed skin can freeze in less than 30 minutes," said a weather forecaster, Scott Reynolds.

In Michigan, where 10 inches of snow north of Detroit made roads dangerous, the storm has claimed at least five lives, authorities said this week. Some died while clearing the snow and others were killed in storm-related crashes.

One hiker in the White Mountains in New Hampshire, who had been out since Monday, was also found dead.

"We are basically experiencing right now the same temperatures as they would up in the Arctic circle range in Canada, up in the Northwest territories or even up toward the pole," Tim Markle, a meteorologist at the Mount Washington Observatory in New Hampshire, said.

"That's very unusual for up here," he added.