A deadly blizzard walloped the eastern United States on Saturday, paralyzing Washington and other cities under a heavy blanket of snow as officials warned millions of people to remain indoors until the storm eases up.
At least eight people were killed in three states in road accidents, officials said, as snow piled up from Arkansas to New York. Forecasters said the storm -- dubbed "Snowzilla" -- would last into Sunday as it moved menacingly up the coast.
Thousands of motorists were stranded for hours on an ice-coated highway in Kentucky. Metro and bus networks were shut down in Washington for the entire weekend, and largely shut in Philadelphia and New Jersey on Saturday.
In the capital Washington more than a foot (30 centimeters) of snow was already on the ground, with another foot expected by midnight.
"There's no reason to be out there," city mayor Muriel Bowser told NBC News. "It will be driving snow and windy and we need to take heed."
City police chief Cathy Lanier said whiteout conditions -- virtually zero visibility -- had been reported in some areas and urged residents to stay indoors so snow plows could work to clear the streets.
A blizzard warning was in effect for a large swath of the eastern United States from Washington up to New York, the National Weather Service said, as battalions of snow plows and salt spreaders labored through the night and into Saturday.
The storm is expected to affect about 85 million Americans -- about one quarter of the US population. Before it's all over, it could cause more than $1 billion in damage, NWS officials said.
"I wouldn't say we're even halfway there yet," Robert Maloney, director of Baltimore's office of emergency management, told CNN.
New Jersey Governor Chris Christie, a Republican presidential contender, left the campaign trail in New Hampshire to oversee the emergency response in his snowbound state.
Christie ordered the state's bus and light rail to stop running at 2:00 am (0700 GMT) Saturday.
"The overall message is, we will get through the storm. We always do. That is the way we do things in NJ," Christie tweeted.
Snow and sleet has already hit the southern states of Arkansas, Tennessee, Kentucky, North Carolina, West Virginia and Virginia -- unusual for the region.
Eighteen states were under blizzard or other winter storm warnings, the Weather Channel reported.
"We're having a lot of accidents," said Pat McCrory, governor of North Carolina.
Six people were killed in road accidents, Nicole Meister, a spokeswoman for the state's emergency management office, told AFP.
Nearly 150,000 people were without power in the state, emergency officials said. CNN reported that power outages had affected another 10,000 elsewhere.
In Kentucky, thousands of motorists became stranded overnight in a backup along a 35-mile (56 kilometer) ice-slickened stretch of Interstate 75, and remained trapped on the road early Saturday.
"I would say we were probably smack dab in the middle of it," one driver, Ben Schmidt, told MSNBC. "We didn't get any sleep."
One person was killed in Kentucky and another in Virginia, officials told AFP.
Thousands of flights were canceled because of the storm, while officials in Washington took the unusual step of closing down the city's rail and bus system from Friday night until Monday morning.
Metrorail -- the second busiest underground train network in the United States after New York -- serves about 700,000 customers a day in Washington, Maryland and Virginia.
In Philadelphia, only two main train lines were running "to help those that need to travel, specifically emergency service and hospital personnel," the Southeastern Pennsylvania Transit Authority (SEPTA) said.
If the blizzard leaves as much snow in Washington as forecast, more than two feet, it could surpass a record set in 1922 by a storm that dumped 28 inches over three days and killed 100 people after a roof collapsed at a theater.
US Capitol Police said they were lifting a decades-old sledding ban, but the national monuments, Capitol building and Smithsonian museums were all closed.
Even a massive snowball fight in Washington's Dupont Circle neighborhood, which nearly 2,000 people said on Facebook they would attend, had to be postponed from Saturday to Sunday due to the storm's ferocity.
Farther north in New York the storm is expected to dump up to a foot of snow.
"Forecasters got it right this time," New York Governor Andrew Cuomo told a news conference. "Unless there is an emergency situation or a critical need, you should not be on the roads."