Superstorm Sandy hurled a wall of water of up to 13 feet high at the Northeast coast, sweeping houses out into the ocean, flooding subway tunnels in New York City and sparking an alert at a nuclear power station in New Jersey.
At least 10 people were killed and more than 7 million were without power as the historic storm pounded some 11 states and the District of Columbia. More than a million people across a dozen states had been ordered to evacuate.
Power outages are expected to be widespread and could last for days. NBC meteorologist Bill Karins warned to "expect the cleanup and power outage restoration to continue right up through Election Day."
New York University Medical Center was moving about 215 patients to other hospitals because its backup generator was out, the hospital said. Critical patients — including infants in neonatal intensive care — were being taken by ambulance to Mount Sinai Hospital, Memorial Sloan-Kettering and New York Presbyterian Hospital.Video: NYU Medical Center evacuates patients (on this page)
The National Weather Service predicted "historic and life-threatening coastal flooding" through Tuesday morning, with the greatest danger coming at high tides. The next high tide will reach New York's Brooklyn Bridge at 9:31 a.m. ET.
Weather.com warned that the high tide Tuesday would result in "additional coastal flooding" from the Delmarva Peninsula to southern New England. Numerous towns along the New Jersey shore, Delaware, Maryland, Virginia, Long Island, Connecticut, Rhode Island, flooded with Monday's morning high tide.
And "in a sign of how extraordinarily large Sandy is" weather.com said that lakeshore flood warnings had been issued for parts of the Great Lakes including Chicago.
The rising waters saw an alert declared at Oyster Creek nuclear power plant in New Jersey at 8:45 p.m. ET, the Nuclear Regulatory Commission said in a statement.
It said the alert was the "second lowest of four NRC action levels" and was "due to water exceeding certain high water level criteria in the plant's water intake structure."Slideshow: Sandy slams into East Coast (on this page)
The NRC spokesman told Reuters that a further water rise could force the country's oldest working plant to use emergency water supplies to cool spent uranium fuel rods — such as water from the fire-suppression system.
The used uranium rods in the pool could cause the water to boil within 25 hours if they are not cooled; in an extreme scenario the rods could overheat, risking the eventual release of radiation, Reuters said.
Exelon said in a statement that there was no danger to equipment and no threat to public health or safety. Exelon spokesman David Tillman said the plant has "multiple and redundant" sources of cooling for the spent fuel pool.
Amid the chaos, firefighters were tackling a massive fire that has destroyed at least 50 houses in a flooded area of the New York borough of Queens, NBCNewYork.com reported. The cause of the fire, which began about 11 p.m. Monday, was not immediately known.Video: 50 homes ravaged by blaze in Queens (on this page)
Reuters reported that one disaster forecasting company was predicting economic losses from the storm, which made landfall at 6:45 p.m. ET, could ultimately reach $20 billion, with only half insured.
The extraordinary storm surge also destroyed a number of houses on Fire Island, New York, where some people had decided to sit out Sandy.
Joe Williams, the commissioner of Suffolk County, told NBC News that "we definitely lost some homes into the ocean."
"One community ... the count right now is about seven. We have numerous homes reported that have collapsed during the storm on Fire Island," he said.
Williams said it was hoped helicopters would be able to survey the damage Tuesday morning with first responders due to arrive on the island by 12 p.m. ET.
"The reports we're getting from Fire Island, most of them -- Fire Island right now is covered in 4 feet of water. So it's impossible for us to land these helicopters but we've been reassured that these people who stayed, most of them are year-round residents. They're pretty strong with this," he said.
Seawater surged into lower Manhattan and areas of Brooklyn, submerging entire streets and parks.
An all-time record tide level of 13.88 feet was set at The Battery in Lower Manhattan, Monday night, breaking the previous record of 11.2 feet from 1821, as well as Sandy Hook, N.J., shattering the previous record from the Dec. 1992 Nor'easter and Hurricane Donna in 1960, according to weather.com.
Mayor Michael Bloomberg said late Monday that New Yorkers threatened their own and other people's lives by going out in the storm. "You have to stay wherever you are," he said.Video: Bloomberg: 'Stay where you are' (on this page)
"DO NOT DRIVE. Call 9-1-1 for emergencies only," the city's Office of Emergency Preparedness said in blast alerts to mobile devices across the city.
A multidwelling structure collapsed on 8th Avenue in New York, NBC New York reported. No one was believed to have been in the two-building, four-story structure, the interiors of which were visible from the street. A crane atop a high-rise building under construction also toppled over and was dangling over the side. Nearby offices and streets were evacuated.Video: Crane hangs from luxury high rise
The powerful storm flooded sections of Atlantic City and other areas of the New Jersey shore. Part of the fabled Atlantic City boardwalk was washed away.
Gov. Chris Christie sharply criticized Atlantic City Mayor Lorenzo Langford, whom he blamed for having "advised people to stay in shelters in the city."
"Despite my admonition to evacuate, he gave them comfort, for some reason, to stay," Christie said, NBCPhiladelphia.com reported.
Dawn Zimmer, mayor of Hoboken, N.J., told MSNBC TV that half the city was flooded and that emergency crews could reach few areas of the city."We want people to be aware that it's a very dangerous situation," she said.Video: Hoboken mayor estimates 50% of city underwater (on this page)
High winds remained a problem. "The National Hurricane Center is forecasting hurricane-force winds from the Maryland/Virginia border to Cape Cod. Persons in these areas should behave as though a hurricane warning is in effect. Do not venture outdoors except in a true emergency," Weather.com added.
16 inches of snow
At least 10 people were killed Monday:
Before it made its way north, Sandy was blamed for the deaths of 65 people in the Caribbean.
The transport network was badly affected with more than 13,000 flights canceled Monday and more than 3,500 called off Tuesday.
Rail traffic was also heavily affected, with Amtrak canceling all of its Northeast Corridor service, in addition to some other lines.
More content from NBCNews.com:
Reuters and The Associated Press contributed to this report.
Sandy: NJ levee breaks; nuclear plant on alert
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