And the New York metropolitan area apparently got the worst of it, because it was on the dangerous northeastern wall of the storm.
"We are looking at the highest storm surges ever recorded" in the Northeast, said Jeff Masters, meteorology director for Weather Underground, a private forecasting service. "The energy of the storm surge is off the charts, basically."
At Cape May, water sloshed over the seawall, and it punched through dunes in other seaside communities.
"When I think about how much water is already in the streets, and how much more is going to come with high tide tonight, this is going to be devastating," said Bob McDevitt, president of the main Atlantic City casino workers union. "I think this is going to be a really bad situation tonight."
In Maryland, at least 100 feet of a fishing pier at the beach resort of Ocean City was destroyed.
At least half a million people along the East Coast had been ordered to evacuate, including 375,000 from low-lying parts of New York City.
Image: This photo provided by 6abc Action News shows the Inlet section of Atlantic City, N.J., as Hurricane Sandy makes it approach, Monday Oct. 29, 2012. Sandy made landfall at 8 p.m. near Atlantic City, which was already mostly under water and saw a piece of its world-famous Boardwalk washed away earlier in the day.