WASHINGTON (AP) -- A treacherous wintry storm slammed the East Coast on Saturday, dumping more than a foot of snow in some areas and creating misery for motorists on the weekend before Christmas.

Officials urged residents to stay indoors, and many heeded the warning. A mall near Richmond, Va., typically busy this time of year, was nearly deserted as stores opened. Airports canceled flights or were operating with excessive delays. Drivers abandoned their cars as roads and highways became impassable.

Forecasts called for up to 20 inches of snow across the region. The nation's capital was blanketed in white.

Snowplows cleared the runway at Andrews Air Force Base in suburban Washington as President Barack Obama returned from climate talks in Copenhagen. The White House said Obama rode in a motorcade back to the White House, instead of taking his helicopter, because of the conditions.

In western Virginia, officials said several hundred motorists became stranded and had to be rescued by four-wheeled vehicles and Humvees driven by the National Guard. About 100 people were taken to shelters in two counties, said Virginia Department of Emergency Management spokesman Bob Spieldenner.

''Some folks have decided to stay in vehicles, others have been taken to shelters,'' Spieldenner said. ''We're definitely trying to keep people off the roads.''

Virginia State Police spokeswoman Corinne Geller said traffic was moving, though slowly. One fatality had been reported, but otherwise there were no medical emergencies, she said.

''It's looks probably a lot worse than it is,'' she said.

At Crump's old country store at the intersection of two country roads outside Richmond, Va., owner Suzanne Rudd stood with a man dressed in a Santa costume and waved to the few motorists. Rudd said only six children had come by.

''Normally we'd have a long line here but people are having a hard time getting out,'' Rudd said. They remained under a carport but were still pelted by thick flakes of snow that also coated windshields and bogged down roads.

Washington Mayor Adrian Fenty had declared a snow emergency for the city and forecasters issued a blizzard warning, saying the conditions could worsen. All of the Smithsonian museums and the National Zoo were closed.

''It's going to be an all day thing. It's going to be on and off,'' said National Weather Service meteorologist Kevin Witt in Sterling, Va.

Philadelphia also declared a snow emergency and the school district canceled all weekend activities.

Reagan National Airport and Dulles International Airport outside Washington each had one runway open, but airlines had canceled most of their flights.

''It's going to be very challenging for people who weren't able to get out today to rebook on flights this week,'' said Tara Hamilton, a spokeswoman for the Metropolitan Washington Airports Authority.

Forecasters said the storm system was expected to generate winds up to 35 miles per hour, which could cause near-whiteout conditions.

People stocked up on groceries and other staples Friday after the National Weather Service issued storm warnings from the Carolinas to Rhode Island. In southern West Virginia, Ron Hart's hardware store was swamped as customers bought heaters and other emergency supplies, just a week after a wind storm knocked out electricity and spawned an earlier emergency shopping surge.

''People are having to spend money on bare essentials versus Christmas,'' Hart said. ''Our Christmas sales are considerably down because of what people are having to buy.''

Forecasters said it could be the most snow in the nation's capital since a February 2003 storm dumped nearly 27 inches at Baltimore-Washington International Airport.

Virginia Gov. Tim Kaine declared a state of emergency ahead of the storm. State Police responded to hundreds of accidents statewide as snow accumulated on interstates and rural roads.

Snow, ice and freezing rain socked western North Carolina on Friday, knocking out power to almost 60,000 customers around the Asheville area.

After a warm start to the ski season that delayed openings of many resorts, the storm arrived just in time for West Virginia's resorts, dumping more than 20 inches on some slopes, said Joe Stevens, a spokesman for the area's ski association.

''These are midseason conditions,'' he said. ''The storm couldn't have come at a better time.''

Highway crews in Maryland, Delaware and the District of Columbia were spraying brine on heavily traveled roads to help prevent snow and ice from sticking.

The storm came from the Gulf and drenched South Florida with rain starting late Thursday, leaving flooded homes and stranded drivers.

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Associated Press Writers Alysia Patterson in Raleigh, N.C., Suzette Laboy in Miami, Alex Dominguez in Baltimore and Jessica Gresko in Washington contributed to this report.