A massive blizzard is barrelling towards the eastern United States, with forecasters predicting that more than 60cm of snow will fall in Washington and a state of emergency declared in five states and the district of Columbia.

The National Weather Service described the storm, which is expected to continue from late Friday until Sunday, as "potentially crippling" for a swath of the country's northeast.

Schools and government offices are being closed, thousands of flights have been cancelled, and food and supplies have disappeared from grocery and hardware stores. Basketball games and concerts have also been postponed.

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Washington's subway system announced that it would shut down entirely from Friday night and remain closed throughout Sunday for the sake of employee and passenger safety. Underground stations usually stay open during major snowstorms.

The director of the National Weather Service told the Associated Press that all the ingredients had come together to create blizzards with brutally high winds, dangerous inland flooding, white-out conditions and even the possibility of thunder snow, when lightning strikes through a snowstorm.

The snowfall could easily cause more than $1bn worth of damage and paralyse the eastern third of the nation, Louis Uccellini, the weather service director, said.

"It does have the potential to be an extremely dangerous storm that can affect more than 50 million people," Uccellini said at the service's Weather Prediction Center in College Park, Maryland.

Washington looks like the eye of the blizzard, and New York City is just inside the slow-moving storm's sharp northern edge, which means that it is likely to see heavy accumulations, he said.

While the storm would not be quite as bad as Superstorm Sandy - the deadliest storm of the 2012 Atlantic hurricane season - people should expect high winds, a storm surge and inland flooding from Delaware to New York, Uccellini added.

Other severe but non-snowy weather is likely from Texas to Florida as the storm system chugs across the Gulf Coast, gaining moisture.

On Thursday, states of emergency were declared in Tennessee, North Carolina, Virginia, Maryland, Pennsylvania and parts of other states, where road crews were out in force.

Blizzard warnings or watches were also in effect along the storm's path, from Arkansas through Tennessee and Kentucky to the mid-Atlantic states and as far north as New York.

The flight tracking site FlightAware estimated that airlines would cancel at least 2,000 flights on Friday and another 3,000 on Saturday. By Sunday afternoon, however, the airlines hoped to be back to full schedule.

A NASA satellite image shows storms developing over the US [EPA via NASA]

Source: Agencies