Sandy knocked out power to at least 3.1 million people, and New York's main utility said large sections of Manhattan had been plunged into darkness by the storm, with 250,000 customers without power as water pressed into the island from three sides.
Just before its center reached land, the storm was stripped of hurricane status, but the distinction was purely technical, based on its shape and internal temperature. It still packed hurricane-force wind, and forecasters were careful to say it remained every bit as dangerous to the 50 million people in its path.
The National Hurricane Center announced at 8 pm that Sandy had come ashore near Atlantic City. It smacked the boarded-up big cities of the Northeast corridor, from Washington and Baltimore to Philadelphia, New York and Boston, with stinging rain and gusts of more than 85 mph (135 kph). The sea surged a record of nearly 13 feet (4 meters) at the foot of Manhattan, flooding the financial district and subway tunnels.
The 10 deaths were in New Jersey, New York, Maryland, Pennsylvania and Connecticut. Police in Toronto said a woman was killed by a falling sign as high winds closed in on Canada's largest city.
As it made its way toward land, it converged with a cold-weather system that turned into a fearsome superstorm, a monstrous hybrid consisting not only of rain and high wind but of snow. Forecasters warned of 20-foot (6-meter) waves bashing into the Chicago lakefront and up to 3 feet (0.9 meters) of snow in West Virginia.
Hundreds of thousands of people were under orders to move to higher ground. The storm knocked out electricity to more than 1 million people, and storm damage was projected at $10 billion to $20 billion, meaning it could prove to be one of the costliest natural disasters in U.S. history.
President Barack Obama and Mitt Romney suspended their campaigning with just over a week to go before Election Day.
At the White House, Obama made a direct appeal to those in harm's way: "Please listen to what your state and local officials are saying. When they tell you to evacuate, you need to evacuate. Don't delay, don't pause, don't question the instructions that are being given, because this is a powerful storm."
The storm washed away a section of the Atlantic City Boardwalk in New Jersey. Water was splashing over the seawalls at the southern tip of Manhattan.
New York City authorities worried that salt water would seep through the boarded-up street grates and through the sandbags placed at subway entrances, crippling the electrical connections needed to operate the subway.
Authorities also feared the surge of seawater could damage the underground electrical and communications lines in lower Manhattan that are vital to the nation's financial center.
Water began pooling in rail yards and on highways near the Hudson River waterfront on Manhattan's far west side. On coastal Long Island, floodwaters swamped cars, downed trees and put neighborhoods under water as beachfronts and fishing villages bore the brunt of the storm. A police car was lost rescuing 14 people from the popular resort Fire Island.
A construction crane atop a luxury high-rise in midtown Manhattan collapsed in high winds and dangled precariously. Residents in surrounding buildings were ordered to move to lower floors and the streets below were cleared, but there were no immediate reports of injuries.
The major American stock exchanges closed for the day, the first unplanned shutdown since the Sept. 11 attacks in 2001. Wall Street expected to remain closed on Tuesday. The United Nations canceled all meetings at its New York headquarters.
Authorities warned that New York City and Long Island could get the worst of the storm surge: an 11-foot (3-meter) onslaught of seawater that could swamp lower Manhattan, flood the subways and damage the underground network of electrical and communications lines that are vital to the nation's financial capital.
"Leave immediately. Conditions are deteriorating very rapidly, and the window for you getting out safely is closing," New York Mayor Michael Bloomberg told those in low-lying areas earlier in the day.
Defiant New Yorkers jogged, pushed strollers and took snapshots of churning New York Harbor during the day Monday, trying to salvage normal routines.
Without most stores and museums open, tourists were left to snap photos of the World Trade Center site, Wall Street and Times Square in largely deserted streets.
Belgian tourist Gerd Van don Mooter-Dedecker, 56, wandered in to Trinity Church after learning that a planned shopping spree with her husband Monday wouldn't happen. "We brought empty suitcases so we could fill them up," she said.
As rain from the leading edges began to fall over the Northeast on Sunday, hundreds of thousands of people from Maryland to Connecticut were ordered to leave low-lying coastal areas, including 375,000 in lower Manhattan and other parts of New York City, 50,000 in Delaware and 30,000 in Atlantic City, New Jersey.
Obama declared emergencies in Massachusetts, Connecticut, Rhode Island, New York, New Jersey and Pennsylvania, authorising federal relief work to begin well ahead of time. He promised the government would "respond big and respond fast" after the storm hits.
New Jersey Gov. Chris Christie was typically blunt: "Don't be stupid. Get out."
Those who stayed in New York had few ways to get out. New York's subways, which serve 5 million people a day, were shut down. The Holland Tunnel connecting New York to New Jersey was closed, as was a tunnel between Brooklyn and Manhattan, and the city planned to shut down the Brooklyn Bridge, the George Washington, the Verrazano-Narrows and several other spans because of high winds.
Off North Carolina, a replica of the 18th-century sailing ship HMS Bounty that was built for the 1962 Marlon Brando movie "Mutiny on the Bounty" went down in the storm, and 14 crew members were rescued by helicopter from rubber lifeboats bobbing in 18-foot (5.5-meter) seas. Another crew member was found hours later and was hospitalized in critical condition. The captain was still missing.
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