An "extremely dangerous" storm has dumped large amounts of snow in the eastern US, killing at least two people and paralysing parts of the region.Up to 28in (71cm) of snow had reportedly fallen by 1100 (1600 GMT) in Washington, which would be the heaviest snowfall there in almost 90 years.
The weather has caused road accidents, cancelled flights, and left tens of thousands of homes without electricity.
A rare blizzard warning is in effect for the Washington-Baltimore area.
The storm - dubbed "snowpocalypse" and "snowmageddon" by the local media - is expected to stretch from Indiana to Pennsylvania and into parts of New York and North Carolina.
It comes less than two months after a December storm dumped more than 16in (41cm) of snow in Washington.
Travel chaos
The National Weather Service has said the storm could be "extremely dangerous."
Washington was left without a bus service after roads were deemed "impassable" and the metro stopped all but its underground service.
The storm has been blamed for at least two deaths - a father and son who were hit by a tractor-trailer on a road in Virginia when they stopped to help a stranded motorist, local media reported.
Most flights were cancelled at the Washington-Baltimore area's three main airports and at Philadelphia International Airport.
Flights from international destinations, including the UK were also disrupted.
In London, British Airways cancelled one flight to Washington and one to Baltimore. Its flights from Philadelphia and Washington to Heathrow were stuck overnight in the US.
Supermarket rush
Officials said at least 150,000 homes had lost power in the Washington area as the wet and heavy snow weighed down trees and power lines.
"Things are fairly manageable, but trees are starting to come down," DC fire department spokesman Pete Piringer, told AP news agency.
Motorists were urged to keep off the roads, church services were cancelled, and people were told to be prepared to stay inside for up to five days.
"DC traditionally panics when it comes to snow. This time, it may be more justifiable than most times," Becky Shipp, a resident of Arlington, Virginia, told AP on Friday.
"I am trying to get a walk in before I am stuck with just the exercise machine in my condo," she added.
As the storm approached on Friday, residents poured into supermarkets, stocking up on food and other supplies, the BBC's Imtiaz Tyab reports from Washington.
One Washington resident described the scene at her local supermarket.
"I got there at 0700 [on Friday] and there were really long queues, Jane Bate, 41, told the AFP news agency. "The place looked like it had been ransacked."
The governors of Virginia, Maryland and Delaware have declared states of emergency, a move that puts the National Guard on alert.
According to the Virginia Department of Transportation, 94% of the state's snow removal budget had already been spent during the December blizzard.
Officials said they would have to use emergency funds to pay for snow removal after this latest storm.
