More than 3,700 flights due to take off on Thursday were cancelled across United States due to the wintry blast, including well over half of flights at the busiest US airport, Atlanta's Hartfield International, airline monitors said.

The National Weather Service began warning days ago that a "mammoth dome" of Arctic air would settle over the eastern United States to form a "paralysing ice storm."

"The ice accumulations remain mind-boggling, if not historical," it said, warning that more than an inch (2.5 centimetres) of ice could fall from Georgia to South Carolina. The massive storm, which stretched from Alabama to Virginia, was also expected to dump as much as a foot (30 centimetres) of snow.

It was set to strengthen as it climbed northward along the eastern seaboard on Thursday, with snowfall totals topping 18 inches by the time the storm reached the far northeastern New England region. Accidents and abandoned cars caused massive traffic jams in North Carolina, with the usually temperate cities of Raleigh and Charlotte transformed into ice- and snow-covered parking lots.

North Carolina Governor Pat McCrory urged residents to stay indoors, even if it means sleeping at work, rather than risk the roads. "If you're in a safe warm place, stay in a safe warm place," McCrory said.

"We've already had two fatalities and we don't want to see more," McCrory added. Two deaths in Georgia were blamed on the storm so far, local media reported. That put the death toll at four, though it was unofficial and still early.

Many Atlanta residents stayed home, after the gridlock caused by a much weaker storm two weeks ago stranded thousands of people. It took days to clear the highway of abandoned vehicles at the time.

 (Agencies)

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