Power remained out for roughly six million people, including a large swath of Manhattan. Early risers stepped out into debris-littered streets that remained mostly deserted as residents awaited dawn to shed light on the extent of the damage. Bridges remained closed and seven subway tunnels under the East River remained flooded.
The storm was the most destructive in the 108-year history of New York City's subway system, said Joseph J. Lhota, the chairman of the Metropolitan Transportation Authority, in an early morning statement. "We are assessing the extent of the damage and beginning the process of recovery," he said, but did not provide a timetable for restoring transit service to a paralyzed city.
At least 16 deaths - including seven in the New York region - were tied to the storm, which toppled trees and sparked fires in several areas, The Associated Press reported.
Nine hours after making landfall at 8 p.m. on Monday, the storm - already downgraded from Hurricane Sandy to a post-tropical cyclone - weakened as it passed west across southern Pennsylvania, though it still packed maximum sustained winds of 65 m.p.h., the National Hurricane Center said. It was expected to turn north and head for Canada late on Tuesday.
The storm had picked up speed as it roared over the Atlantic Ocean on Monday, grinding life to a halt for millions of people in more than a half-dozen states, with extensive evacuations that turned shorefront neighborhoods into ghost towns.
Hurricane-force winds extended up to 175 miles from the center of the storm; tropical-storm-force winds spread out 485 miles from the center. Forecasters said tropical-storm-force winds could stretch all the way north to Canada and all the way west to the Great Lakes. Heavy snow was expected in some states.
Businesses and schools were closed; roads were closed; and more than 13,000 airline flights were canceled. Even the Erie Canal was shut down.
Subways were shut down from Boston to Washington, as were Amtrak and the commuter rail lines. About 1,000 flights were canceled at each of the three major airports in the New York City area. Philadelphia International Airport had 1,200 canceled flights, according to FlightAware, a data provider in Houston. And late Monday night, Mayor Michael R. Bloomberg said cabs had been instructed to get off New York City roads.
The wind-driven rain lashed sea walls and protective barriers in places like Atlantic City, where the Boardwalk was damaged as water forced its way inland. Foam was spitting, and the sand gave in to the waves along the beach at Sandy Hook, N.J., at the entrance to New York Harbor. Water was thigh-high on the streets in Sea Bright, N.J., a three-mile sand-sliver of a town where the ocean joined the Shrewsbury River.
"It's the worst I've seen," said David Arnold, watching the storm from his longtime home in Long Branch, N.J. "The ocean is in the road, there are trees down everywhere. I've never seen it this bad."
In Breezy Point on the Rockaways, nearly 200 firefighters were still battling a blaze on Tuesday morning that destroyed at least 50 tightly-packed homes in the beach community. A Fire Department spokesman said the area was "probably the most flooded part of the city, so there are all sorts of complications."
The surging water also caused extensive complications at NYU Langone Medical Center when a backup power system failed Monday evening, forcing the evacuation of patients to other facilities. Backup power also failed at Coney Island Hospital in southern Brooklyn, though critical patients had been evacuated in advance of the storm.
In New York, Gov. Andrew M. Cuomo's office said late Monday night that at least five deaths, at least three involving falling trees, were attributable to the storm in the state. About 7 p.m., a tree fell on a house in Queens, killing a 30-year-old man, the city police said. About the same time, two boys, ages 11 and 13, were killed in North Salem in Westchester County, when a tree fell on the house they were in, according to the State Police.
In Morris County, N.J., a man and a woman were killed when a tree fell on their car Monday evening, The Associated Press reported.
Earlier, a construction crane atop one of the tallest buildings in the city came loose and dangled 80 stories over West 57th Street, across the street from Carnegie Hall.
As the storm lashed the city, waves topped the sea wall in the financial district in Manhattan, sending cars floating down streets. West Street, along the western edge of Lower Manhattan, looked like a river. The Brooklyn-Battery Tunnel, known officially as the Hugh L. Carey Tunnel in memory of a former governor, flooded "from end to end," the Metropolitan Transportation Authority said, hours after Governor Cuomo of New York ordered it closed to traffic. Officials said water also seeped into seven subway tunnels under the East River.
"In 108 years, our employees have never faced a challenge like the one that confronts us now," Mr. Lhota, the transit authority chairman, said.
A replica of the H.M.S. Bounty, a tall ship built for the 1962 movie "Mutiny on the Bounty" starring Marlon Brando and used in the recent "Pirates of the Caribbean" series, sank off the North Carolina coast. The Coast Guard said the 180-foot three-masted ship went down near the Outer Banks after being battered by 18-foot-high seas and thrashed by 40-m.p.h. winds.
The body of one crew member, Claudene Christian, 42, was recovered. Another crew member remained missing.
Delaware banned cars and trucks from state roadways for other than "essential personnel."
"The most important thing right now is for people to use common sense," Gov. Jack Markell said. "We didn't want people out on the road going to work and not being able to get home again."
By early Monday evening, the storm knocked out power to hundreds of thousands of homes, stores and office buildings. Consolidated Edison said that as of 1:30 a.m. Tuesday, 634,000 customers in New York City and Westchester County were without power. Con Edison, fearing damage to its electrical equipment, shut down power pre-emptively in sections of Lower Manhattan on Monday evening, and then, at 8:30 p.m., an unplanned failure, probably caused by flooding in substations, knocked out power to most of Manhattan below Midtown, about 250,000 customers. Later, an explosion at a Con Ed substation on East 14th Street knocked out power to another 250,000 customers.
In New Jersey, more than two million customers were without power as of 1:30 a.m. Tuesday, and in Connecticut nearly 500,000.
President Obama, who returned to the White House and met with top advisers, said Monday that the storm would disrupt the rhythms of daily life in the states it hit. "Transportation is going to be tied up for a long time," he said, adding that besides flooding, there would probably be widespread power failures. He said utility companies had lined up crews to begin making repairs. But he cautioned that it could be slow going.
"The fact is, a lot of these emergency crews are not going to get into position to start restoring power until some of these winds die down," the president said. He added, "That may take several days."
Forecasters attributed the power of the storm to a convergence of weather systems. As the hurricane swirled north in the Atlantic and then pivoted toward land, a wintry storm was heading toward it from the west, and cold air was blowing south from the Arctic. The hurricane left more than 60 people dead in the Caribbean before it began crawling toward the Northeast.
"The days ahead are going to be very difficult, Gov. Martin O'Malley of Maryland said. "There will be people who die and are killed in this storm," he said.
Alex Sosnowski, a senior meteorologist with AccuWeather, said potentially damaging winds would continue on Tuesday from Illinois to the Carolinas - and as far north as Maine - as the storm barreled toward the eastern Great Lakes.
Mr. Cuomo, who ordered many of the most heavily used bridges and tunnels in New York City closed, warned that storm surges from could go two feet higher than that associated with Tropical Storm Irene last year. The PATH system, buses and the Staten Island Ferry system were also suspended.
The storm headed toward land with weather that was episodic: a strong gust of wind one minute, then mist. More wind. Thin sheets of rain dancing down the street. Then, for a moment, nothing. The sky lightened. Then another blast of rain. Then more wind.
In some places, caravans of power-company trucks traveled largely empty roads; Public Service Electric and Gas said that 600 line workers and 526 tree workers had arrived from across the country, but could not start the repairs and cleanup until the wind had subsided, perhaps not until Wednesday.
They will see a landscape that, in many places, was remade by the storm. In Montauk, at the end of Long Island, a 50-seat restaurant broke in half. Half of the building floated away and broke into pieces on the beach.
The 110-foot-tall lighthouse at Montauk Point - the oldest in the state, opened in 1796 - shuddered in the storm despite walls that are six feet thick at the base. The lighthouse keeper, Marge Winski, said she had never felt anything like that in 26 years on the job.
"I went up in the tower and it was vibrating, it was shaking," she said. "I got out of it real quick. I've been here through hurricanes, and nor'easters, but nothing this bad."
Reporting on the storm was contributed by Peter Applebome, Charles V. Bagli, Joseph Berger, Nina Bernstein, Cara Buckley, Russ Buettner, David W. Chen, Annie Correal, Sam Dolnick, Christopher Drew, David W. Dunlap, Ann Farmer, Lisa W. Foderaro, Joseph Goldstein, David M. Halbfinger, Elizabeth A. Harris, Winnie Hu, Jon Hurdle, Thomas Kaplan, Corey Kilgannon, John Leland, Randy Leonard, Patrick McGeehan, Jad Mouawad, Colin Moynihan, Sarah Maslin Nir, Sharon Otterman, William K. Rashbaum, Ray Rivera, Liz Robbins, Wendy Ruderman, Nate Schweber, Michael Schwirtz, Mosi Secret, Kirk Semple, Joe Sharkey, Brian Stelter, Kate Taylor, Julie Turkewitz, Matthew L. Wald, Michael Wilson, Michael Winerip, Vivian Yee and Kate Zernike.