Residents clear their cars and street of snow in Weehawken, New Jersey, as the skyline of Manhattan and the Hudson River are seen after a snowstorm in New York, US March 14, 2017. [Photo/Agencies]

NEW YORK/BOSTON - A late-season snowstorm swept the mid-Atlantic and northeastern United States on Tuesday, closing public school systems from Washington, D.C., to Boston, grounding thousands of airline flights and knocking out electricity to 200,000 customers.

Tens of millions of residents from Maryland to Maine faced a "rapidly intensifying Nor'easter" that was rare for its arrival in mid-March, just a week before the official end of winter, according to the National Weather Service (NWS).