Blizzard conditions are causing severe disruption along the eastern coast of the United States.
More than 1000 flights have been cancelled at airports in the New York area, and the main international airport, JFK, has been closed.
Travellers were stranded at varous airports across the north-east of the US, with little prospect of reaching their destination.
The rail operator Amtrak has suspended services between New York and Boston, where more than 30 centimetres of snow is expected.
Maryland, Virginia and North Carolina have declared states of emergency; blizzard warnings are in effect for Rhode Island and most of eastern Massachusetts including Boston; and severe weather warnings are in place from Georgia to Vermont as temperatures plummet.
South Carolina had its first Christmas snow since records began in 1887.
Transport officials in Washington DC deployed 200 salting lorries, snow ploughs and other equipment to tackle the expected deep snow expected along the eastern seaboard.
