It was forecast to dump icy drizzle and eventually freezing rain through the New York City area and into Boston, National Weather Service meteorologist Greg Heavener said.
Indeed, slippery conditions were reported overnight in the New York City area: One crash involving about 20 vehicles closed lanes of an interstate highway in Greenwich, Connecticut, for a couple of hours.
No serious injuries were immediately reported.
Forecasters said air travel would likely remain a hassle, too.
“I think the further north you look, departures and arrivals could be affected because of icy issues,” Heavener said.
What was forecast in the Philadelphia area to be a tame storm system with about an inch of snow gradually changing over to rain mushroomed into a full-blown snowstorm. Bands of heavy snow made for a wide range of accumulation: a foot was reported in Newark, Delaware.
Philadelphia International Airport received 8.6 inches (218 millimeters), more than it had all of last year.
Sunday's snow fell so heavily in Philadelphia that yard markers at the city's National Football League stadium, where the Eagles beat the Detroit Lions, were completely obscured.
It was almost as bad in Pittsburgh, where the snow intensified after the opening kickoff.
Heavy snow in the Philadelphia area led to a number of accidents, including a fatal crash on the Pennsylvania Turnpike that spawned fender-benders involving 50 cars, stranding some motorists for up to seven hours.
More than two dozen vehicles were involved in another series of crashes on a nearby interstate highway.
Stacey Jackson, a spokeswoman for the Philadelphia airport, said Sunday a number of passengers were expected to remain in the airport overnight since area hotels had been full for several days. She said staff would hand out pillows and blankets to travelers to make them “feel at home even though they are not.”
Air passengers in the Washington-area experienced increasing delays at both Dulles International and Ronald Reagan Washington National airports.
Virginia, parts of West Virginia and the metropolitan Washington area braced for blackouts under steady freezing rain, wet snow and sleet.
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