“The loss estimates for a recurrence of the 1821 storm . . . would be in excess of all storms which recently impacted the Eastern Seaboard,” the report concludes.
Compared to Sandy, the 1821 storm’s wind field was more severe and storm surge flooding affected a larger area of the Mid-Atlantic and Northeast shoreline.
Considering the trillions of dollars in infrastructure and assets in the path of such a storm today, Swiss Re says a repeat would be a “a paradigm shifter, severely and negatively impacting the economy and altering the culture going forward.”
The storm, known as the 1821 Norfolk Long Island Hurricane, ripped up the Mid-Atlantic and Northeast coast September 3 and 4 – coinciding with Labor Day (before the holiday was established). The report summarizes the horrifying toll over a sprawling area:
Coastal communities in North Carolina were washed away, ships in Norfolk were pushed ashore, and the Delaware Bay flooded Cape May. On eastern Long Island, the aftermath was described by locals as, “the most awful and desolating event ever experienced.” The hurricane was a devastating event for the expanse of Northeast United States, with communities, farms, and churches laid in ruins from North Carolina to New Hampshire. The storm’s wind field was immense with hurricane force winds recorded as far north as Maine.
Sprinting up the coast after initial contact with the Carolina Outer Banks, the storm – which may have initially made landfall at Category 4 intensity – only slowly weakened.
“I haven’t seen anything comparable [in the historical record this far north],” said Megan Linkin, the report’s author. “Perhaps the Great Beaufort storm of 1879 compares. Hugo and Hazel were also Cat 4s, but first hit in South Carolina.”
Linkin said the track was similar to 2011’s Irene but that it was stronger and maintained its intensity longer.
“Its center passed over Cape Henlopen [Del.] and Cape May [N.J.],” Linkin said. “Observers reported a 15 to 30 minute calm, demonstrating the storm still had a well-defined eye and had not weakened much.”
The editor of the Norfolk Herald described “general devastation” in Norfolk, where most of downtown was flooded, Linkin said.
Reports from the Maryland and Delaware beaches were few as the region – now heavily developed with high rise condos, businesses, and expensive vacation homes – was lightly inhabited at the time. But estimated wind gusts in this region exceeded 100 mph.
Surge flooding, given the storm track paralleling the coast – placing the Delmarva shore in the storm’s most dangerous northeast quadrant – would have been extremely damaging. In the southern Delmarva, the water rose 10 feet in Pungoteague, Va., Linkin said.
Swiss Re’s modeling suggests the damage from wind alone (not including surge) from a similar storm today would generate $3 billion in damages in Virginia Beach, $430 million in Worcester County, Md. (which includes Ocean City and Berlin), and $467 million in Sussex County, Del. (which includes Fenwick, Bethany, and Rehoboth).
The return period of such a storm is probably around every 200 years Swiss Re determined. Linkin said it could be considered a “low-end black swan event” which refers to a very low probability but extremely high impact disaster.
“The whole point [of analyzing the 1821 storm] was to remind everyone there have been bad events historically,” Linkin said. “Just because there hasn’t been an event this bad in recent memory, there’s no reason to become complacent and think the Northeast and Mid-Atlantic are immune to these kinds of storms.”
On the New York Times DotEarth blog, Linkin told science journalist Andrew Revkin “increasing coastal resilience is critical” (through floodwalls, levee systems, and relocating vulnerable infrastructure, for example) to confront the risk of such a damaging storm in the future.