Workers prepare to treat the steps of the US Capitol with ice melting salt in Washington January 22, 2016. [Photo/Agencies]

The National Weather Service said it was too soon to tell whether the snowfall will break records around Washington D.C. and Baltimore. "Either way, we're looking at a significant event," said NWS meteorologist Frank Pereira.

The full force of the storm could dump enough snow on Washington to eclipse the 17.8 inches (45.2 cm) of a 2010 storm and total snowfall might rival the storm of 1922, when a record 28 inches fell.

The storm developed along the Gulf Coast, dropping snow over Arkansas, Tennessee and Kentucky on Friday. On the East Coast, warm, moist air from the Atlantic Ocean collided with cold air to form the massive winter system, Pereira said.

"This has life-and-death implications and all the residents of the District of Columbia should treat it that way," Washington Mayor Muriel Bowser said.

The storm was forecast to move offshore in southern New England early next week. Philadelphia and New York were expected to get 12-18 inches of snow before the storm abated.