Powerful snowstorm blankets US east coast
A snowstorm has hit the US East Coast, just a day after unseasonably balmy temperatures.
Meteorologists predict the busy Philadelphia-to-Boston corridor, where millions live, could get between 12-18in (30-45cm) of snow.
New York, Boston and Philadelphia have closed public schools for the day, and commuters were advised to stay indoors.
More than 3,300 flights have been cancelled, and numerous car accidents have been reported.
New Jersey's emergency management officials reported about 50 collisions in Thursday morning's commute.
"If you need to go out, please, don't use your car," New York Mayor Bill de Blasio said on local television.
The snowfall comes amid a relatively snow-less winter for the East Coast.