WASHINGTON The powerful blizzard that slammed the East Coast on Saturday quickly surpassed forecasters' dire predictions, claiming at least 18 lives, flooding coasts, unleashing hurricane-force winds and paralyzing life for residents of at least 20 states from Georgia to Massachusetts.

The storm was well on its way to smashing snowfall records.

Mayors and governors said they did not expect their cities to be back in business until next week.

"We are going into uncharted territory here," New York Gov. Andrew Cuomo warned as the heart of the storm hit his state. Visibility was so low that those walking across the Brooklyn Bridge couldn't see the East River beneath it or the Manhattan skyline soaring above.

Cuomo took the rare step of banning all travel in the nation's largest city Saturday. Drivers who failed to stay off the roads in New York City were ticketed, and trains and large segments of the subway system, the lifeblood of the city, were shut down. Minutes before imposing the travel ban, Cuomo saw the risk firsthand when he helped a crew rescue a driver whose car had spun out on Long Island's Cross Island Parkway.

Many who tried to drive through the storm elsewhere soon regretted it, as icy and snow-covered roadways from Kentucky to Pennsylvania stranded motorists for hours behind crashed cars and whiteout conditions.

"We've hit the 24 hour mark on the bus!" the Temple University women's gymnastics team tweeted from the Pennsylvania Turnpike on Saturday afternoon. The athletes watched Disney movies to pass the time, according to their tweets.

Another bus full of college athletes stuck on the same highway, the Duquesne University men's basketball team, hiked nearly a mile through more than 2 feet of snow to meet a Domino's driver so they could eat, according to their social media account.

Along New Jersey and Delaware's coastlines, Saturday's storm caused ice-laden seawater to rush into the streets of beach towns. The same area _ a network of low-lying communities, brackish bays and dune-covered oceanfront _ was hit hard by Superstorm Sandy in 2012.

"The barrier islands here are very narrow, so it's usually the bay that breaches," said Chip French, an Avalon, N.J., resident whose town sits on a narrow stretch of land alongside the Atlantic Ocean. "We have ice floes going down the streets of the barrier islands right now."

The snow was being whipped by winds that reached 75 mph at Dewey Beach in Delaware and Langley Air Force Base in Virginia, according to the National Weather Service.

Most of the East Coast was expecting snow totals close to 2 feet, with 25 to 30 inches expected in New York City, at least 30 inches reported in parts of Maryland, and 40 inches reported by an amateur radio operator in Glengary, W.Va.

More than 10,000 flights around the country were canceled between Friday and Sunday, most of them due to the storm, according to Flightaware.com, which tracks airline service. Tens of thousands of homes were without electricity.

By late afternoon, about 20 inches of snow had been reported in Washington and New York, with little sign of high winds and rising snow levels letting up. Both totals were among the highest ever recorded in those cities.

"I used to like it," Barbara Enman of Brooklyn said of snow as she shoveled her front steps. "It is pretty, though."

But also perilous.

"It continues to be a dangerous storm," Washington Mayor Muriel Bowser warned during a late-afternoon news briefing. Bowser pleaded with residents to sign up online to help the elderly and disabled clear their sidewalks, saying the city had been inundated with calls for help and could not meet the demand.

Forecasters said the blizzard's final flakes would probably fall sometime Sunday afternoon in southeastern Massachusetts.

Parked cars up and down the Eastern Seaboard were buried and barely visible under the blankets of white. Normally bustling streets in New York, Philadelphia and Washington were quiet, with occasional sledders and sightseers, but few businesses open for a night on the town.

"It's a once-in-a-lifetime experience," said Paul Mikula, who hauled his snowboard to Times Square in New York and shredded the snow under the neon lights.

Most small shops along that stretch of Broadway, which normally would have been open for steady weekend trade, had closed by about 2 p.m. Remaining open and doing brisk business were several bars and restaurants and a hardware store, where a woman exited with her young daughter and a brand-new sled.

Families coming out of subway tunnels carrying sledding saucers were hit by wind and snow as they tried to make their way to Central Park, where visibility at times was zero.

Across the region, streets remained vacant except for snowplows, which tried, often in vain, to keep up with the relentless outpouring.

"There are very few roads where we're seeing pavement right now," said Chris Geldart, the emergency management director for the District of Columbia.

Other areas saw extensive flooding. The National Weather Service reported major, near-record flooding along Delaware's coast.

Throughout the storm's path, there was danger that as the snow got heavier overnight, roofs and trees could falter. And as residents began to shovel, those with heart conditions could be at risk.

Rick Hoffman of Frederick, Md., had worked through the night plowing a small corner of Montgomery County with his blue Ford pick-up truck. He was still at it midday Saturday, but couldn't keep up with the continuous pelting of snow.

"It's one of the worst I've seen," said the 57-year-old Hoffman, who has worked as a snow-removal contractor for decades. What made things particularly treacherous, he said, was that the light texture of the snow coming down produced a sheath of ice underneath.

In Gaithersburg, a Maryland suburb north of Washington, Mark Hesseloff was up early Saturday, his 47th birthday, digging an 8-by-6 clearing outside his snow-covered apartment complex. His face was drenched with a mixture of sweat and ice as he scooped sections of snow with his orange shovel.

"This will be a perfect little spot for them," he said, referring to his two bulldogs, who had had been cooped up since Friday afternoon. Moments later, one of them, 8-year-old Blondie, hobbled outside, relieved. "Yup, she's been waiting," he said.