Swift snowstorm rolls through northeastern US

A major snowstorm rolled across the northeastern United States on Tuesday, with forecasters calling for as much as a foot (30 centimeters) of snow in some places before it leaves a cold snap in its wake.

Downtown Washington fell virtually silent after the federal government, seeing the swift-moving cold front approaching, closed its doors and told civil servants -- who Monday had the day off for the Martin Luther King holiday -- to stay home.

Many offices and schools followed suit, as 20 mile (32 kilometer) per hour winds whipped the falling snow through the unusually quiet streets.

Washington's Metro system reported half as many riders as a typical weekday, and business was so slow that many restaurants used Twitter to woo customers with bargain-priced drinks.

Enough snow was expected to fall on the US capital to turn the evening rush hour into a Beltway traffic nightmare, as the storm churned its way into New York and the northeastern New England states.

"The storm along the Mid-Atlantic Coast will deepen rapidly while moving northeastward to the Canadian Maritimes paralleling the coast by Wednesday evening," the National Weather Service said.

"The system will produce moderate to heavy snow over the mid-Atlantic coast into southern New England that will move into the Gulf of Maine by Wednesday morning."

In its wake, the storm will see temperatures drop as low as eight degrees Fahrenheit (minus 13 Celsius) in Washington overnight -- with the mercury unlikely to climb back above freezing before Saturday.

FlightAware, a website that monitors air traffic in real time, said nearly 3,000 flights into, out of or within the United States had been cancelled Tuesday.

The lion's share of affected flights involved busy airports in the New York, Philadelphia and Washington areas.

National passenger rail operator Amtrak said it would operate "a normal Tuesday schedule," but it warned passengers to "anticipate some weather-related delays."

Private forecasting service AccuWeather call for snowfalls to be heaviest along a band stretching from the Canadian province of Nova Scotia and the northeasternmost state of Maine down the Atlantic seaboard into Virginia.

"Travel conditions will deteriorate rapidly due to slippery roads and diminishing visibility," AccuWeather said.

"As the air turns colder, the snow will become dry and powdery. Increasing winds will cause extensive blowing and drifting snow."

The Washington Post's popular Capital Weather Gang blog forecast up to 10 inches of snow in and around the US capital, ahead of a return of sub-freezing temperatures later this week.

Organizers of Wednesday's annual March for Life rally on the National Mall, which typically draws tens of thousands of Americans who oppose abortion, said they were going ahead with the event.

In New York, a storm alert remained in effect until 6:00 am (1100 GMT) Wednesday with as much as a foot (30 centimeters) forecast for the metropolitan region.

Temperatures were set to fall below normal, to as low as 10 degrees Fahrenheit (minus 12 Celsius) with winds gusting to 35 miles (56 kilometers) per hour.

Dozens of schools either closed for the day or told parents to expect their youngsters to be dismissed from class earlier than usual. Courthouses called off proceedings in the afternoon.

Across the Hudson River, New Jersey went ahead with its mid-day inauguration ceremony for re-elected governor Chris Christie, who is battling allegations he used his office to bully political foes.

But an evening gala on historic Ellis Island in New York Harbor to mark the start of his new term in office was cancelled due to the storm.

What the National Weather Service called a "fast moving but potent" snowstorm had earlier dumped seven inches of snow on airports the Chicago area, before temperatures fell to the freezing level.