The misery of superstorm Sandy's devastation grew Tuesday as millions along the U.S. East Coast faced life without power or mass transit for days, and huge swaths of New York City remained eerily quiet.
The U.S. death toll climbed to 48, many of the victims killed by falling trees, and rescue work continued.
The storm that made landfall in New Jersey on Monday evening with hurricane force cut power to more than 8.2 million across the East and put the presidential campaign on hold just one week before Election Day.
New York was among the hardest hit, with its financial heart closed for a second day. The storm caused the worst damage in the 108-year history of the city's subway system, and there was no indication of when the largest U.S. transit system would be rolling again.
"This was a devastating storm, maybe the worst that we have ever experienced," New York City Mayor Michael Bloomberg said.
But the full extent of the damage in New Jersey was being revealed as morning arrived. Emergency crews fanned out to rescue hundreds.
The death toll from Sandy in the U.S. included several killed by falling trees. Sandy also killed 69 people in the Caribbean before making its way up the Eastern Seaboard.
Airlines cancelled more than 12,000 flights. New York City's three major airports remained closed.
Most major tunnels and bridges in New York were closed, as were schools and Broadway theatres.
Around midday Tuesday, Sandy was about 190 kilometres east of Pittsburgh in Pennsylvania, pushing westward with winds of 72 kph, and was expected to make a turn into New York State on Tuesday night. Although weakening as it goes, the storm will continue to bring heavy rain and flooding, said Daniel Brown of the National Hurricane Center in Miami. Sandy also brought blizzard conditions to West Virginia and neighbouring Appalachian states, with 60 centimetres of snow expected in some places.
Sandy will end up causing about $20 billion in property damage and $10 billion to $30 billion more in lost business, making it one of the costliest natural disasters on record in the U.S., according to IHS Global Insight, a forecasting firm.
President Barack Obama declared a major disaster in New York and Long Island, making federal funding available to residents of the area. He suspended campaigning for a third day Wednesday.
Obama, speaking during a stop Tuesday at Red Cross headquarters, warned the public that the massive storm that struck the East Coast "is not yet over." He said there were still risks of flooding and downed power lines. He called the storm "heartbreaking for the nation."
The president offered his thoughts and prayers to those affected and told them "America is with you." He said he also told government officials co-ordinating the response that there was "no excuse for inaction."
And he said he told governors in affected areas that if they get no for an answer, "they can call me personally at the White House."
Republican challenger Mitt Romney resumed his campaign, but with plans to turn a political rally in Ohio into a "storm relief event."
Trading at the New York Stock Exchange was cancelled again Tuesday after the storm sent a nearly four-and-a-half metre surge of seawater, a record, coursing over its seawalls and highways and into low-lying streets. The water inundated tunnels, subway stations and the electrical system that powers Wall Street and sent hospital patients and tourists scrambling for safety. Skyscrapers swayed and creaked in winds that partially toppled a crane 74 stories above Midtown. A large tanker ship ran aground on the city's Staten Island.
A fire raged in a neighbourhood Tuesday morning in the borough of Queens, near the Atlantic Ocean, with 80 to 100 homes destroyed but no deaths reported.
Around 670,000 customers were without power in and around New York City.
In New Jersey, a huge swell of water swept over the small town of Moonachie, and authorities struggled to rescue about 800 people, some of them living in a trailer park. Police and fire officials used boats to try to reach the stranded.
As Hurricane Sandy closed in on the Northeast, it converged with a cold-weather system that turned it into a monstrous hybrid of rain and high winds -- even bringing snow in West Virginia and other mountainous areas inland.
While the hurricane's 144 km/h winds registered as only a Category 1 on a scale of five, it packed "astoundingly low" barometric pressure, giving it terrific energy to push water inland, said Kerry Emanuel, a professor of meteorology at MIT.
New York University's Tisch Hospital was forced to evacuate 200 patients after its backup generator failed. NYU Medical Dean Robert Grossman said patients -- among them 20 babies from the neonatal intensive care unit who were on battery-powered respirators -- had to be carried down staircases and to dozens of ambulances waiting to take them to other hospitals.
With files from The Canadian and Associated Press