Barack Obama has declared New York a "major disaster" after Americans awoke to scenes of devastation.President
Hurricane Sandy hit the East coast of the US overnight, leaving at least 17 people dead and over seven million without power.
New York was inundated with record levels of floodwater, causing what was described by authorities as the worst disruption in history to the city's transport network.
"The New York City subway system is 108 years old, but it has never faced a disaster as devastating as what we experienced last night," said Joseph Lhota, chairman of the Metropolitan Transportation Authority (MTA).
The hurricane has also ripped through big cities of the Northeast corridor, from Washington and Baltimore to Philadelphia, New York and Boston.
Among the 16 dead in New York were two children killed instantly by a falling tree, a woman electrocuted to death by falling wires in Manhattan and a 29-year-old man killed in a car crash in Queens.
Sandy is moving westward across southern Pennsylvania with winds of 65mph and is expected to move into Canada on Wednesday.