All non-essential travel has been banned in New York, transport suspended and bridges shut as the city is hit by one of its worst snowstorms.
Parts of the eastern United States have received 40in (102cm) of snowfall in a huge blizzard that is sweeping across the region.
Travel restrictions in New York came into place at 14:30 (19:30 GMT).
Mayor Bill de Blasio said up to 25in snow may fall, making it one of the five worst winter storms in the city.
Heavy snow began falling on Friday across more than 20 states, affecting some 85 million people.
At least 13 people have died and emergencies have been declared in 11 states.
Tens of thousands of homes are without power and traffic jams lasting more than 12 hours were reported in Kentucky and Pennsylvania.
The heaviest unofficial snowfalls recorded by mid-afternoon included:
• 40in (102cm) – Berkeley County, West Virginia
• 35.5in (90cm) – Morgan County, West Virginia
• 34in (86cm) – Washington County, Maryland
The weather system affects a huge swathe of the country, from Alabama in the south to Massachusetts in the north-east.
New York City could be on course to top its highest snowfall, 26.9in, recorded in February 2006.
In the latest developments in New York:
• Governor Andrew Cuomo has declared a state of emergency
• Almost all flights into the city have been cancelled
• Tunnels into New York have also been closed
• Emergency vehicles and workers carrying out repairs are being allowed to use roads – but those driving non-essential vehicles risk being arrested
• Above-ground and subway train services were suspended from 16:00 local time (21:00 GMT)
“This is going to be one of those generational events, where your parents talk about how bad it was,” said Ryan Maue, a meteorologist with WeatherBell Analytics.
On the Pennsylvania Turnpike, several hundred people have been stranded in vehicles for almost a day.
Among them are close to 250 students from the University of Mary in North Dakota. Monsignor James Shea, president of the university, told the BBC that “spirits are good and no-one is panicking”.
Further south in Kentucky, a 35-mile (56km) traffic jam has cleared, after thousands of drivers found themselves stranded overnight on Interstate 75 by heavy snow and a number of accidents.
The Red Cross erected shelters along the highway for those left in the traffic jam.
In other developments:
• More than 4,300 flights were cancelled in the eastern US on Saturday alone
• One man died on Saturday of an apparent heart attack while shovelling snow in Maryland; the other 12 to die since the storm hit the US were killed in car accidents
• More than 150,000 properties lost power in North Carolina
• Another 90,000 people were without power in New Jersey, while high tides have led to some heavy flooding in the south of the state
• States of emergency have been declared in New York, Tennessee, Georgia, Kentucky, North Carolina, New Jersey, Virginia, West Virginia, Maryland, Pennsylvania, the District of Columbia
The US federal government closed down at noon on Friday. President Obama is remaining at the White House.
In a warning on Saturday morning, the National Weather Service tweeted that an “intense snow band” was moving across the eastern states. “Expect rapid accumulations and near-whiteout conditions,” it warned.
Residents in the capital and surrounding suburbs in Virginia and Maryland have been warned the snowfall could eclipse the district’s record of 28in that fell during a two-day period in 1922. – BBC News