A massive snowstorm has brought much of the eastern US to a standstill, affecting some 85 million people.
The blizzard has dumped 40in (102cm) of snow in some areas, with 11 states declaring emergencies.
All non-essential travel is banned in New York, with officials believing it could be one of the city's worst snowstorms.
At least 18 deaths - many from traffic accidents - have been blamed on the severe weather since Friday.
In all, 20 states have been affected by the fierce storm.
Tens of thousands of homes are now without power and traffic jams lasting more than 12 hours were reported in Kentucky and Pennsylvania on Saturday.
In rural Virginia - parts of which had more than 30in of snow - there were more than 1,000 car crashes and two people died of hypothermia.
The heaviest unofficial snowfalls recorded by mid-afternoon on Saturday included:
In New York, travel restrictions came into effect in the city at at 14:30 (19:30 GMT), with transport being suspended and bridges shut.
Emergency vehicles and workers carrying out repairs are being allowed to use roads - but those driving non-essential vehicles risk being arrested
Almost all flights into the city have been cancelled.
Mayor Bill de Blasio said up to 28in of snow might fall, making it one of the five worst winter storms in the city.
New York's highest previous snowfall, 26.9in, was recorded in February 2006.
"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.(BBC)