The storm approached New England on the cusp of the winter solstice, having already caused flooding in South Florida and knocked out electricity for more than 85,000 customers in the Carolinas on Friday. On Saturday, it dropped 16 inches of snow on Reagan National Airport outside Washington - the most ever recorded there for a single December day - and gave southern New Jersey its highest single-storm snowfall totals in nearly four years.
Some of the deepest snow Saturday was recorded in the Philadelphia suburb of Medford, N.J., at 24 inches.
"For those who are looking for a white Christmas, this certainly will stick around for Christmastime," National Weather Service meteorologist Bruce Sullivan told AP Radio.
Even the NFL, with its hallowed tradition of playing in all weather conditions, including football fields nicknamed "frozen tundras," pushed back the scheduled start times of games Sunday in Baltimore and Philadelphia.
Around New York City, the brunt of the storm hit Long Island, with nearly 2 feet recorded in Upton. Crews clearing roads early Sunday reported whiteout conditions, said Lt. Robert P. Iberger of the Southampton police.
Ten inches of snow had already fallen on New York City by Sunday morning, and the storm could be the worst the city has seen since about 26 inches fell in Central Park in February 2006, National Weather Service meteorologist Patrick Maloit said. Transit workers in New York were clearing subway tracks and platforms overnight, and delays were expected on bus, subway and train routes, city transit spokesman Paul Fleuranges said early Sunday.
The National Weather Service expected the storm to dump as much as 15 inches in southern New England with the heaviest snowfall expected early Sunday. A blizzard warning was in effect Sunday morning in parts of New York, Rhode Island and Massachusetts.
With strong wind gusts to keep the powdery snow swirling, the storm was so bad on Saturday that attractions such as the Smithsonian museums in Washington and the Philadelphia Zoo were closed. The National Mall, normally swarming with tourists, instead was the scene of snowball fights.
Not all shoppers were deterred by the snow.
"It really helped me get in the Christmas spirit," said the Kathryn Mariani, who took a train to downtown Philadelphia from her home in the Germantown neighborhood.
The mayors of Washington and Philadelphia and the governors of Virginia, West Virginia, Kentucky, Maryland and Delaware all declared states of emergency.
In West Virginia, blankets were given to hundreds of drivers, and some motorists were stranded for up to 27 hours on highways, Red Cross spokesman Jeff Morris said.
The storm hit on the last weekend before Christmas, a time when roads are traditionally mad with holiday shoppers. But around shopping centers in Philadelphia's New Jersey suburbs on Saturday, traffic was sparse and slow.
Prime parking spots were available all day at the Cherry Hill Mall. And inside, there was no line for a picture with Santa. "It was fantastic," said Chris Bailey, who got pictures of his 4-year-old daughter Olivia.
Shops at the mall and nearby restaurants closed hours early.
Salt trucks and plows were out in force. The speed limit was reduced on several roadways, including the New Jersey Turnpike. But those measures didn't prevent scores of cars from slipping into ditches.
One person in Virginia was killed in a traffic accident caused by slick roads, and authorities said the weather may have contributed to another traffic death there. A third death in Virginia is believed to have been caused by exposure. In Ohio, two people were killed in accidents on snow-covered roads hit by the same storm system.
In New Jersey, a bus got stuck on snow-covered railroad tracks in Pennsauken and was hit by a train. The 26 passengers were evacuated from the bus 10 minutes before the crash, and the only reported injury was a minor one suffered by the train's engineer, NJ Transit spokesman Dan Stessel said.
Greyhound shut down service in Washington and points north, and ferry service in Delaware and New Jersey was canceled.
Airports in the Northeast were also jammed up. Most flights were canceled at several, including Reagan National and Dulles in the Washington area; Philadelphia International; New York's three major airports and Logan Airport in Boston. The cancellations rippled across the country; more than 150 flights were canceled in and out of Chicago's airports, as were a handful in Denver.
Philadelphia Airport spokeswoman Phyllis VanIstendal said snacks and pillows were being handed out there to travelers stranded overnight.
She said with continuing bad weather and planes out of place, problems would continue Sunday.
At National, Juan Carlos Franco waited in line Saturday with his wife, 2-year-old son and 6-month-old daughter to rebook their flights to Quito, Ecuador, but was expecting to fly out no sooner than Wednesday. They had checked and rechecked the status of their flight for two days, but it wasn't canceled until a few minutes after they entered the security line, Franco said.
"The backpacks were in the X-ray machine," he said.
Associated Press writers Sarah Karush in Washington; Dena Potter in Chesterfield, Va.; Jacob Jordan in Atlanta; David Porter in Atlantic City, N.J.; Bruce Shipkowski in Trenton, N.J.; Ron Todt and Patrick Walters in Philadelphia; and AP photographer Jacquelyn Martin in Arlington, Va., contributed to this report.