At least nine people have died in the US and 10 states have declared emergencies as Storm Jonas edges across the country and air travel continues to be impacted.
Thick snow covered the Washington DC area on Saturday as a potentially record-breaking blizzard paralysed road, rail and airline travel on the US east coast from North Carolina to New York.
More than 85 million people in at least 20 states were covered by a winter weather warning, watch or advisory, the Weather Channel said, and many stores were left with bare shelves as residents stocked up on food, water and wine, preparing to spend the weekend indoors.
Supermarket shelves were emptied in anticipation of what could be the worst storm in nearly 100 years.
Residents were urged to have enough food and water for 72 hours as city officials warned that the clean-up would not begin until late on Saturday, when the snowfall eased.
The governors of several states, including New Jersey, Pennsylvania, Maryland, Virginia, North Carolina and Georgia, as well as the mayor of Washington, declared states of emergency. Steady snow was falling on southeastern Pennsylvania, including Philadelphia, early on Saturday. The storm is forecast to head north toward New York City later in the day.
The National Weather Service said it was too soon to tell whether the snowfall will break records around Washington DC and Baltimore.
"This has life-and-death implications and all the residents of the District of Columbia should treat it that way," Washington Mayor Muriel Bowser said.
The storm was forecast to move offshore in southern New England early next week. Philadelphia and New York were expected to get 12-18 inches of snow before the storm abated.
Low-lying areas of New York and New Jersey - some still rebuilding after Superstorm Sandy in 2012 - might see flooding during high tides on Saturday and Sunday, officials said.
It is thought there are thousands of homes currently without power and buses in New York have been suspended as heavy snow continues to fall in what the mayor, Bill de Blasio, has called one of the worst snow storms to hit the city.
Trains, planes More than 7,200 flights were cancelled within, into or out of the United States on Friday and Saturday, according to flight tracking website FlightAware.com. Amtrak modified service on train routes along its busy Northeast Corridor.
The Washington Metropolitan Area Transit Authority, which includes the country’s second-busiest subway system, took the rare step of suspending operations from late Friday through Sunday.
New Jersey Transit shut all bus, rail and light rail service early on Saturday and said service would be restored as “conditions permit”.
Government offices closed at noon on Friday and DC schools remained shut.
The snow forecast could surpass the Knickerbocker storm of 1922, which dropped 28 inches on Washington. It took its name from a theatre were 98 people were killed when its flat roof collapsed under the weight of the snow.
The last storms to hit Washington, in December 2009 and February 2010 – known as “Snowmageddon” and “Snowpocalypse” – dumped 16 inches and nearly 18 inches of snow respectively.
Additional reporting from agencies
