Near-blizzard conditions are expected to slam into New York on Wednesday evening, in the biggest storm to hit the city since January 2016. Bill de Blasio has announced schools will be shut on Thursday.
Up to two feet of snow are being forecast for inland areas in Pennsylvania, New York State, and much of Connecticut, Rhode Island and Massachusetts.
The cities of Washington DC and Philadelphia will be sitting right on the dividing line between precipitation types, making for a messy mix of snow, sleet, freezing rain and possibly, cold rain as the storm intensifies and moves along the East Coast.
People are being told to avoid all but essential travel.
Airlines have cancelled 700 flights and delayed almost 400 due to the impending storm.