The big one: The East Coast's USD 100 billion event

Publication draws on history to paint a scenario that will help plan for the future.

Two years have passed since Hurricane Sandy roared ashore and rewrote the record books. Although much of the northeastern United States has rebounded and life has generally returned to normal, the trauma is still very real to many.

Sandy is generally regarded as a 1-in-500-year event - with its exceptional size, perpendicular track to the coast and record-breaking low pressure.

As bad as it was, Sandy could have been worse. While the storm offered many new lessons to modelers, underwriters and coastal communities, it shouldn’t be the only catastrophe benchmark in the quest for improved resiliency. To fully understand the vulnerability of the Eastern Seaboard and prepare for future extreme events, it’s important to re-examine hurricanes of greater magnitude.

It has happened before

Nearly 200 years ago a major hurricane pummeled the entire Mid-Atlantic and Northeast - from Norfolk to Washington, DC to Boston. The 1821 Norfolk and Long Island hurricane made landfall on the coast of North Carolina with wind gusts above 156 mph and carved a path of devastation up and down the Eastern Seaboard, making subsequent landfalls in Delaware, New Jersey and New York. Only 136,000 people lived in New York City and Washington at the time and losses were modest by today’s standards. There was no such thing as radar, satellites or the National Weather Service, yet there were many vivid accounts and records, which can be extrapolated to the present to create instructive assumptions.

Past plus present equals future   

A new report from Swiss Re, The big one: The East Coast's USD 100 billion event (PDF, 730 KB) examines how the 1821 hurricane would impact the region today. Trillions of dollars of assets and infrastructure would lie in the storm’s path, much of it aging and along the coast. Using our in-house, proprietary tropical cyclone model we reconstructed the storm track, wind field and potential storm surge and concluded that a large area of the most heavily developed Eastern Seaboard would be exposed to hurricane force wind gusts.

Storm surge comparable to Sandy would inundate New York City, accompanied by powerful winds gusting over 100 mph. Norfolk, Virginia - home of critical US Navy installations - would be completely flooded. Coastal counties would sustain wind damage alone in excess of USD 1 billion. Combined physical damage from both storm surge and wind would exceed USD 100 billion, while the storm's total potential economic impact is on the order of USD 150 billion.

Hurricane Sandy was a wake-up call; if left unheeded, the 1821 Norfolk and Long Island hurricane would be the nightmare.

Published 18 September 2014


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