Hurricane Sandy is threatening to turn into a "super storm" which could have a "devastating landfall" within 100 miles of New York, forecasters have warned, as winds picked up to 90mph.
Atlantic City is already underwater, with warnings that it could be the worst storm to hit the city in 50 years, after the category one storm battered the east coast of America early on Monday.
Hurricane Sandy is predicted to hit near New York City around 8pm US eastern time (12am GMT).
Much of Atlantic city is under water and the boardwalk has been washed away
The "life-threatening" storm surge that is expected to hit the entire east coast is likely to be compounded by high tides brought about by the full moon and could be up to 11ft (3.4-metre) high.
Sandy has already killed 67 people in the Caribbean over the past week.
Hurricane Sandy is about 520 miles (835km) across and is only moving at 20mph, meaning that it could cover 12 states for 24-36 hours, bringing up to 25cm of rain, 60cm of snow.
Dr Jane Strachan, Willis Research Fellow at the University of Reading, said: “Although only a category 1 hurricane, Sandy is causing big problems for the U. S. northeastern states due to its huge size and slow movement up the U. S. East Coast.
"Powerful winds, torrential rains and storm surges threaten states from the Carolinas to New England."
Power companies have told residents to prepare to be without power for up to 10 days.
A state of emergency have been declared in nine states including Maryland, New York, Pennsylvania, Virginia and Washington DC, ahead of the expected a Category 1 hurricane.
1,500 members of the National Guard have been mobilised to provide emergency assistance.
Thousands of people have been evacuated from their homes in New York and evacuation shelters have been set up around the city.
The city's transport system has ground to a halt and the New York Stock Exchange will be fully closed on Monday and Tuesday, its operator said.
Kamran Moazami, Head of Buildings Structures at engineering consultancy WSP and the structural engineer on the Freedom Tower in New York, said: “New York is a city of skyscrapers but tall buildings are designed to withstand high wind loads – we design structures for a 50 year wind event, up to 98 miles per hour and on top of that structures are designed for a factor of safety.
"The parts of the city that will suffer the most are the smaller structures and the infrastructure which makes up the nervous centre of the city.
"As in any disaster it is the lack of water, power and transport and flooding that can have the most devastating impact and effect on the speed of recovery.”
President Barack Obama urged Americans "to take this very seriously and follow the instructions of your state and local officials, because they are going to be providing you with the best advice in terms of how to deal with this storm over the coming days".
Brits are unable to get to or from the area, with flights cancelled across the East Coast and fears many could be stranded for days.
Air France, British Airways and Virgin Atlantic have grounded all of Monday's flights on both sides of the Atlantic to and from New York, Baltimore, Newark, Washington, Boston and Philadelphia.
Sandy has had a dramatic effect on the US presidential campaign. Barack Obama pulled out of a planned visit to Florida and is instead over-seeing emergency operations, painfully aware that hoe he handles to crisis could affect his election hopes.
Mitt Romney also cancelled planed election visits.