Two years ago today, Super-storm Sandy slammed the New York City tri-state area. Despite being downgraded from hurricane to post-tropical status just prior to landfall, Sandy was the second costliest natural disaster in U.S. history, following Hurricane Katrina in 2005. The question is, can it happen again?
Coming ashore with tropical storm-force winds at high tide during a full moon, Sandy was an unprecedented storm. It formed late in the season, grew as it moved north, and instead of turning out to sea like most tropical systems, it made that now famous left hook toward the coast. Statistically, Sandy’s unusual trajectory was a 1-in-700-year event, according to a recent study by researchers at NASA and Columbia University. That said, as sea levels continue to rise, future storm surges will have a higher starting point and be able to reach further inland. So, a lesser storm could produce similar, if not worse, flooding in the future. A different study in the journal, Nature Climate Change, predicts that a current “500 year” storm surge event in NYC could happen every 50 to 240 years by the end of the century.
Sandy caused a record 13.88-foot storm surge at the Battery in lower Manhattan. It flooded many low-lying areas, including parts of the NYC subway system. The massive storm, according to the CDC, directly claimed the lives of 117 people in the U.S – mostly by drowning. Damaging or destroying more than 650,000 homes, Sandy displaced thousands of people and caused approximately $70 billion in property damage in addition to knocking out power to 8.5 million people for multiple days.
In reaction, many government agencies – at all levels – have been re-evaluating their strategies for dealing with future storm surge flood disasters. The National Hurricane Center changed its policy for issuing warnings on post-tropical storms and has developed an experimental Potential Storm Surge Flooding Map that depicts the risk associated with a storm surge during a tropical cyclone. In NYC, the Office of Emergency Management re-drew its hurricane evacuation zones to reflect the threat of higher sea levels.
As these types of important improvements are being made, the arduous process of rebuilding homes and installing physical defenses against future storms is still ongoing, especially in the region’s hardest hit areas.