|Subterranean basement of Financial District, New York, USA ... on Tuesday|
At least 39 people have been killed, millions are without power and transport across the north-eastern United States has been severely disrupted as storm Sandy heads north for Canada.
In New York City, 10 people have been killed and the public transport system remains closed until further notice.
In New Jersey, three people were killed, including a couple killed by a falling tree when they got out of their car; their children, 11 and 14, who remained inside, survived.
A woman in West Virginia died when her car collided with a cement lorry, in heavy snow caused by the storm.
New Jersey Governor Chris Christie said 2.4 million households in the state had been affected, double the number hit by Hurricane Irene in August 2011.
The devastation was “beyond anything I thought I’d ever see,” Christie told a news conference.
The Path commuter train service, which links New Jersey and New York City, is likely to remain suspended for seven to 10 days, Christie said.
The tidal surge from the storm left fields of debris 7ft (2.25m) high and carried small railway goods cars onto elevated sections of the New Jersey Turnpike, he said.
More than 15,000 flights were cancelled in US, the flight-tracking website FlightAware estimates.
Earlier, Sandy killed more than 60 people as it hit the Caribbean.
Sandy brought a record storm surge of almost 14ft (4.2m) to central Manhattan, well above the previous record of 10 feet (3m) during Hurricane Donna in 1960, the National Weather Service said.
The storm was causing heavy snowfalls over the Appalachian mountains on Tuesday afternoon. It was expected to turn towards western New York state during the evening before moving into Canada on Wednesday, the forecaster said.
At least eight million homes and businesses are without power because of the storm, says the US Department of Energy, the BBC reports.
The New York Stock Exchange says it will re-open on Wednesday after two days’ closure, as will the Nasdaq exchange. The last time the stock exchange shut down for two days was in 1888.
New York’s subway system sustained the worst damage in its 108-year history, said Joseph Lhota, head of the Metropolitan Transit Authority (MTA).
Subway tunnels were flooded and electrical equipment will have to be cleaned before the network can re-open.
New York Mayor Michael Bloomberg said there was “no timeline” for when the subway would restart, but he hoped buses could begin running again on Wednesday.
All New York’s major airports are closed as their runways are flooded.
It is likely to be two or three days before power is restored to most of the city, Mr Bloomberg said.
Meanwhile, US President Barack Obama has declared “major disasters” in the northeastern states of New York and New Jersey where a massive storm named Sandy raked over the region, flooding low-lying streets and wiping out power across much of region.
Tuesday’s declarations free up federal disaster funds to help with disaster relief efforts.
The storm moved ashore late Monday south of New York with hurricane-strength winds. It weakened as it moved inland.
Obama will travel to New Jersey on Wednesday to view storm damage from Sandy with Republican Governor Chris Christie, the White House said.
Obama will also visit victims of the huge storm and will thank “first responders who put their lives at risk to protect their communities,” White House spokesman Jay Carney said in a statement.