A snow emergency has been declared in New York City amid a blizzard that could dump up to 90cm (3ft) of snow on the US north-east coast.
Mayor Bill de Blasio said vehicles would not be allowed on the city's 6,000 miles of roads after 23:00 local.
"We need to recognise this as an emergency, this is not business as usual," Mr de Blasio said.
Heavy snowfall is forecast from Philadelphia to Maine, falling up to four inches an hour in some areas.
Four states have declared emergencies - New York, New Jersey, Connecticut and Massachusetts - and a blizzard warning issued for an area inhabited by 20 million people.