Doug Stanglin, Doyle Rice, Jessica Estepa, and Matt Krantz

USA TODAY

New York City and Long Island were under a travel ban Saturday, including all transit from New Jersey bridges and tunnels into and out of the city as a deadly blizzard left major cities, roadways and airports along the East Coast largely immobilized.

More than 60 million people were under blizzard, winter storm or freezing rain warnings as the storm's effects stretched from Georgia to Massachusetts, according to Weather.com. More than 80 million people are in the storm's path, says the Associated Press.

Some 250,000 customers were without power as the storm roared up the East Coast, according to the Weather Channel.

The storm officially achieved blizzard status late Saturday in Washington, D.C., the National Weather Service said.

At least 18 people died in storm-related incidents in Tennessee, Kentucky, Maryland, North Carolina and Virginia, The Associated Press reported. In Fort Washington, Md., one man died of an apparent heart attack while shoveling snow.

Blizzard 2016: 10,000 flight cancellations and counting

Eleven states from Georgia to New York declared states of emergency.

Air traffic ground to a halt across much of East Coast, with more than 10,000 flights canceled nationwide by Saturday afternoon. Underscoring the severity of the storm, all flights were halted Saturday at four of the nation’s busiest airports: Philadelphia, Washington Dulles, Washington Reagan National and Baltimore/Washington International.

Public transportation in Philadelphia, Baltimore and Washington, D.C., was also shut down as local officials called on residents to hunker down and stay off the streets for a second day.

“This event has all the makings of a multibillion-dollar economic cost,” said meteorologist Steven Bowen of Aon Benfield, a London-based global reinsurance firm. After adding up damage to homes, vehicles, businesses and more, "we're potentially looking at one of the costlier winter storm events in recent memory,” he said.

The so-called Blizzard of 1996, which had a similar size and scope, had a $4.6 billion economic cost (in 2016 dollars), Bowen said. “No two events are identical, but this provides some context as to how costly these storms can be.”

As New York City's travel ban took effect, the National Weather Service predicted 24-30 inches of snow for the metropolitan area, putting it within range of the city's biggest snowstorm on record, 26.9 inches received in 2006.

The order, effective mid-afternoon, shut down state highways and two major routes on Long Island. Above-ground subway stations in New York City were also being closed as the storm continued to pound the area.

Under the ban, only emergency vehicles will be allowed on the streets, and drivers who ignore the order could face heavy fines and license points, New York Gov. Andrew Cuomo said. New York City Mayor Bill de Blasio announced shortly before 6 p.m. that the travel ban, initially scheduled to expire at midnight, had been extended until Sunday morning.

In response, all Broadway matinees and evening performances for Saturday night were canceled, according to The Broadway League, the official website of the Broadway theater industry.

Asked for advice for parents whose kids want to frolic in the snow, de Blasio laced empathy with caution.

"If you want to go really quickly to someplace near your home, stay with your kids — adult supervision necessary," he said. "This is a vastly intensifying storm and it’s slippery, it’s gusty. I, as a parent, wouldn't let my kids out of my sight."

Blizzard 2016: 10,000 flight cancellations and counting

'Stay at home and off the roads'

The heaviest snow fell across Maryland and Delaware earlier Saturday before shifting toward southern New York, Connecticut, Rhode Island and southeast Massachusetts, the National Weather Service said.

The top snowfall total from the storm so far is 40 inches in Glengary, W.Va., the weather service reported. Many locations across West Virginia, Maryland and Virginia. topped 2 feet, with more on the way.

Maryland Governor Larry Hogan on Saturday ordered the closure of a nearly 35-mile stretch of I-270 and I-70. Those roadways were to be shut down ending Sunday at 7 a.m. The closures kick in following a number of traffic incidents.

“Now is the time for Marylanders to stay at home and off the roads,” Hogan said. “This is the safe choice. It will also allow emergency services vehicles to maneuver and road crews to begin the long process of clearing highways and streets."

Baltimore Mayor Stephanie Rawlings-Blake ordered cars without chains or snow tires to stay off the streets to avoid creating problems for snow removal, The Baltimore Sun reported.

On Capitol Hill in Washington, people emerged in the early afternoon to shovel their sidewalks, dig out their cars and walk their dogs. Some wore skis to get around, others dragged sleds toward the Capitol, where they could legally ride the sleds this year. But by 3 p.m., the snowfall picked up once again and visibility diminished.

Washington Mayor Muriel Bowser urged residents not only to stay off the roads in vehicles but also not to walk on the snow-covered streets. She said too many people were walking down the middle of the largely empty streets, hampering the work of snow plows and endangering themselves.

"Visibility is poor and you cannot be seen," Bowser said. "We need you to stay home."

In Delaware, Gov. Jack Markell banned all but essential personnel from driving on the roadways in Kent and New Castle counties.

"With so much snow accumulating on our roads, conditions are becoming dangerous for any more traffic than absolutely necessary," Markell said Saturday, The News-Journal reported.

Tidal flooding swamps coastal areas

Along the Delaware and New Jersey coasts, icy floodwaters pushed inland by the storm were surging into neighborhoods.

In Sea Isle, N.J., tidal flooding sent a river of ice flowing several blocks down JFK Boulevard through a major retail area. Darren Laricks, a dispatcher with the Sea Isle police department, said the water was beginning to recede in the main street before noon but was expected to return at high tide after 7 p.m.

"We're just waiting for the water to subside," Laricks said.

He said no injuries were reported from the high water, which, Laricks said, was almost as high as during Superstorm Sandy in 2012.

“When the water just started rushing down, it was as impressive as some of the videos you saw of Japan during the tsunamis,” said Jason Pellegrini, owner of Steak Out restaurant in Sea Isle City, who was trapped inside by floodwaters. “It came in that fast,” he told AP.

In New York City, with 6 inches already on the ground, snow was falling at up to 3 inches per hour Saturday morning, according to Kathryn Garcia, commissioner of the city’s Department of Sanitation.

City sanitation trucks, equipped with plows and tire chains, were making repeated clearing runs on streets across the city’s five boroughs. “We are trying to stay ahead of the storm, but it is a pretty intense storm,” Garcia told WCBS Newsradio 88 shortly before 8 a.m.

Cuomo said state officials were paying close attention to ocean and river storm surges during high tides.

“It was higher than usual, but it was not problematic,” Cuomo told NY1 News.

While many New Yorkers heeded warnings to stay home, Abdul Rahman worked his normal 6 a.m.-to-6 p.m. Saturday shift at Punjab, a south Asian deli and newspaper outlet in Manhattan’s Gramercy Park neighborhood.

Few customers came during the Saturday storm for their usual orders of chai tea or coffee, but one stood transfixed watching a cricket match on the store’s TV.

“It’s slow, because most people know they don’t have to go to work, but it’s fine,” said Rahman, who said the snow reminded him of similar wintry weather in Pakistan’s Punjab region. “But my family says it’s too cold."

Trapped on highway for hours

Outside the big cities, travelers were not faring much better, as thousands of accidents were reported.

Virginia State Police reported 989 car crashes statewide by late Friday and had assisted nearly 800 disabled vehicles, said Ken Schrad, spokesman for the Virginia State Police Joint Information Center.

Blizzard 2016: 10,000 flight cancellations and counting

In Pennsylvania, the National Guard was sent in to help motorists stranded along the westbound lanes of the Pennsylvania Turnpike in Bedford and Somerset counties, officials said, according to PennLive. Some travelers reported being stuck for at least 10 hours after several tractor-trailers had trouble climbing a steep portion of the roadway near the Allegheny Mountain Tunnel in Somerset County.

The problems prompted the closure of a long section of the turnpike from Breezewood to New Stanton in central Pennsylvania.

Large portions of Interstate 75 in Kentucky were in gridlock for hours,with a 6-mile backup at one point because of wreckage, AP reported. State trooper Kendra Wilson told CNN on Saturday morning that some people had been trapped on the highway for more than 12 hours.

Mike Edmonds was stuck at a truck stop in Kentucky on Friday as snow piled up around him, not daring to venture his big rig out of the slick parking lot and onto an interstate strewn with wrecked vehicles, he told the AP by phone.

"We've got trucks here that literally cannot get out," Edmonds said. "We're spinning. It's not worth even getting out on the road."

More havoc for travelers

Model behavior: Computers saw blizzard coming

All of the precipitation associated with the storm should move off the Atlantic coast before sunrise Sunday, leaving clearing skies for the day, Weather.com reported.

The storm will likely cause havoc for travelers into Monday. It could easily cause more than $1 billion in damage, weather service director Louis Uccellini said.

Daniel Baker, CEO of FlightAware.com, said the blizzard proved worse than anticipated and led to more flight cancellations Sunday, for a total of 10,246 for the weekend by 5 p.m. Saturday. Airlines now expect a full recovery of their schedules Monday, he said.

United Airlines, which has a hub at Washington Dulles airport, announced it would not resume service in Washington on Sunday and would be running a limited schedule at New Jersey's Newark, Baker said.

Many travelers were forced to modify their plans in creative ways. Two buses with 85 students traveling to Washington to mark the anniversary of the Supreme Court's 1973 Roe v. Wade ruling were stranded on the interstate in Pennsylvania for 19 hours while trying to return home to Sioux Falls, S.D., on Friday, the Argus Leader reported.

The group built an altar out of snow. “It was still snowing while we had Mass. There was singing and cheering,” Rev. Shaun Haggerty of the Catholic Diocese of Sioux Falls said.

Contributing: Kevin McCoy in New York, Bart Jansen, Laura Petrecca, Joseph Schartz (Argus Leader)