Parts of the eastern United States have received more than two feet (71cm) of snow fall in a huge blizzard that is sweeping across the region.
Heavy snow began falling on Friday across more than 20 states, affecting some 85 million people.
New York City mayor Bill de Blasio said the storm could be one of the worst to ever hit the city. He is considering a travel ban.
At least nine people have died and emergencies declared in 10 states.
Tens of thousands of homes are without power and traffic jams lasting at least 12 hours have been reported in Kentucky and Pennsylvania.
The nation’s capital, Washington, could lie under a record 30in (76cm) of snow by the time the storm passes on Sunday. At the White House, 13in (33cm) of snow fell overnight.
The weather system affects a huge swathe of the country, from Alabama in the south to Massachusetts in the north-east.
Mr de Blasio said New York City was now expecting up to two feet of snow, which would make it one of the five largest storms ever to hit the city.
In a press conference, he urged citizens to get off the road. “This is bad and getting worse rapidly,” his office tweeted.
In Kentucky, a 35-mile (56km) traffic jam has started to clear in the past few hours, after thousands of drivers found themselves stranded on Interstate 75 overnight by heavy snow and a number of accidents.
The Red Cross erected shelters along the highway and Kentucky State Police tweeted that officers were taking water, fuel and snacks to the motorists, some of whom had been stuck for more than 12 hours.
Further north, on the Pennsylvania Turnpike, a number of other vehicles have been stuck in snow for at least 12 hours after the road closed. One university basketball team that was stranded said they were running out of leftover pizza and getting hungry.
The US federal government closed down at noon on Friday. President Obama is remaining at the White House.
The National Weather Service (NWS) warned that the worst of the snow would fall in the Washington area from the early hours of Saturday to the early afternoon, with winds of more than 50mph (80kph).
In a warning at 02:17 (07:17 GMT), the NWS tweeted that an “intense snow band” was moving through the area. “Expect rapid accumulations and near-whiteout conditions,” it warned.
The most intense parts of the snowstorm are heading north towards New York State on Saturday.