Hurricane Sandy-Level Floods Likely to Hit NYC More Often

​By Charles Q. Choi, Live Science Contributor | October 11, 2016 02:51pm ET

Disastrous floods like those seen during Hurricane Sandy in 2012, which killed 159 people in the United States, destroyed neighborhoods in New York and caused an estimated $50 billion in damages, may hit New York City 17 times more often in the next century, a new study finds.
Hurricane Sandy was the second costliest hurricane in U.S. history, according to the National Hurricane Center. The hurricane caused widespread flooding of streets, buildings and subway tunnels in Manhattan after storm surges pushed the East River to overflow its banks.
The storm surge, or storm-linked rise in sea level from Sandy, reached 9.2 feet (2.8 meters) in New York City, and the storm tide — the combined height of the normal ocean tide and the storm surge — reached a record height of 11.3 feet (3.44 meters) there. A better understanding of how often such catastrophic flooding might happen is key to minimizing future damages, the researchers said. [A History of Destruction: 8 Great Hurricanes]

The scientists found that from 1800 to 2000, the chances of Sandy-level floods have tripled from once every 1,200 years to once every 400 years due to factors such as the slow sinking of the land in the mid-Atlantic region in response to the end of the last ice age. In addition, based solely on how the rate of sea-level rise is expected to accelerate over the 21st century, the researchers estimated that flooding on a par with Hurricane Sandy would become 4.4 times more likely by the end of this century.
"It was a big change in flood frequency that we found, especially comparing this century to the past two centuries," Lin told Live Science.
Even if the number of strong hurricanes does not increase between now and 2100, sea-level rise alone will likely increase the frequency of Sandy-like events, according to study co-author Ben Horton, a professor in the Department of Marine and Coastal Science at Rutgers University. 

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