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What if the 1821 Long Island Hurricane happened today?

The details of this storm remain fuzzy. Based on first hand accounts and somewhat spotty meteorological data, we can only know one thing — the Long Island Hurricane of 1821 was a big deal. It was one of only four known tropical cyclones to make landfall in New York City. It made landfall just several hours prior, near Cape May, New Jersey as what would now be defined a strong Category 3 Hurricane. And then, it tracked northward essentially along the Garden State Parkway, briefly back out into open water and then through New York Harbor. The storm struck at low tide, but still produced a near-30 foot storm surge along much of the New Jersey Coast, obliterating any development there and causing significant overwash past the shores.

Obviously, this storm occurred in 1821 — way, way before any major development by modern standards. Areas which were hammered with unprecedented wind, rain and storm surge from the Hurricane of 1821 now are populated by the millions — with incredible development and modernization. A new report, from the ReInsurance behemoth SwissRe, details what would happen if a storm similar to the Hurricane of 1821 occurred today. And the results are not good.

From their report, which is laced with model graphics and imagery as well as simulations:

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.

 

From a meteorological standpoint, the Hurricane of 1821 was a behemoth of its own. Initial observations from the storm begin hundreds of miles off the Southeast Coast of the United States. The storm is said to have tracked northwestward, through the Bahamas and closer to the Southeastern United States. Observations and records bring sustained winds over 135 miles per hour, with some arguing that the storm reached Category 5 standards. The storm eventually would make landfall near Wilmington North Carolina while turning northward, presumably on the periphery of a Western and Central Atlantic Ridge.

Estimated track of the 1821 Hurricane based on observations and reprots.

Estimated track of the 1821 Hurricane based on observations and reports.

The storm would then track northward, crossing the Chesapeake Bay toward the Delaware coastline. It would re-emerge over the open waters of the Mid-Atlantic Coast before making landfall near Cape May New Jersey, and eventually again in New York City. First hand accounts bring to light the degree of impact:

 The hurricane produced a surge of 13 feet  in only one hour at Battery Park, a record only broken 191 years later by Hurricane Sandy. Modern day Manhattan was completely flooded all the way to Canal Street. 

A storm surge similar to the Hurricane of 1821 — or, meteorologically, one with similar initial conditions and track — would devastate the area to a further extent than Hurricane Sandy. Lower Manhattan would be completely underwater — most of the Jersey Shore would be as well. And the winds would cause immeasurable damage to infrastructure and property.

SwissRe simulation of flooding in Lower Manhattan from a storm similar to the 1821 Hurricane. Hurricane Sandy flooded this area in a similar, but less extensive fashion.

SwissRe simulation of flooding in Lower Manhattan from a storm similar to the 1821 Hurricane. Hurricane Sandy flooded this area in a similar, but less extensive fashion.

What does this all mean? Right now, not too much. But what it should tell us is that these storms, like Hurricane Sandy, aren’t a one time deal. We happen to live in quite  a vulnerable location for storms like these.  From an insurance standpoint, the research is good marketing material (it’s a very good report — don’t get us wrong). But from a meteorological standpoint, the research is a stark reminder of the fact that storms of this magnitude happen — and it is up to us to prepare for them.

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