Over the past 48 hours, thousands of flights have been canceled or disrupted.
New York City's three major airports remained closed on October 29.
Operators shut down units at several nuclear power plants as a safety precaution.
In the wake of the storm, up to a million people had been ordered to evacuate their homes.
But by the time Sandy was reaching its peak late on October 29, New York Mayor Michael Bloomberg said evacuations were no longer possible.
"If you're in your home or somewhere safe where you can remain, stay there," he said. "The time for relocation or evacuation is over. Conditions outside are dangerous and they are only going to get worse in the hours ahead."
The full extent of the damage is still not clear. Analysts say it is expected to be amount to tens of billions of dollars.
Sandy has disrupted campaigning just one week before the U.S. presidential elections.
Both Obama and his Republican Party challenger, Mitt Romney, have canceled campaign events as a result of the storm.
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