By MATTHEW BRODSKY, senior editor/Web editor of Risk & Insurance®
In what could be a very busy hurricane season in 2010, one or more of our coastal communities might be due to experience the horrors of storm surge. But thanks to new insurance-related research and hurricane forecasting tools, hopefully the local population and businesses will be better prepared for the wall of water.
The latest bit of insurance-related research on storm surge was released last week by First American Spatial Solutions, the mapping technology subsidiary of First American Corp. The report analyzes the impact of hurricane storm surge on 13 cities along the U.S. Atlantic and Gulf coasts.
The researchers picked these communities based on a number of factors, including the probability of a future hurricane hit, the density of property value and vulnerability to storm surge. The last factor is determined by the topography of the coastline and its bathymetry, or its underwater topography approaching the coast. Hurricanes create huge swells of water underneath them and the high winds push the highest waters to the storms' edges. Like a tsunami, this storm surge water grows higher and higher as the ocean floor gets shallower and shallower closer to the coast.
According to the research, the towns most exposed to a Category-1 storm were New Orleans and Miami, to a Cat-5 storm Miami (again) and Virginia Beach. As much as $53 billion in property could be exposed if a Cat-5 storm hit the Miami-Dade area; more than $39 billion in Virginia Beach.
"Virginia Beach was the area that surprised us the most as we did not expect the residential property risk to be so high," said Howard Botts, vice president and director of database development for First American.
Other cities on the list could experience potential losses that are not small potatoes either.
A Cat-2 hit to the Gulf Shores and Mobile, Ala., areas would expose nearly $1 billion in property to storm surge and flood most of downtown Mobile. Long Island would see nearly $11 billion in property exposed to storm surge from a Cat-4 hurricane. A Cat-3 hit to Jacksonville could inundate much of downtown and the nearby beach communities. Other cities in the study included: Brownsville, Texas; Charleston, S.C.; Corpus Christi, Texas; Houston; Myrtle Beach, S.C.; Tampa; and Wilmington, N.C.
The researchers only examined potential losses to residential properties, for two reasons. The firm's residential valuation data provided "granularity" when run against its storm surge model, according to Botts. Additionally, residential property owners are usually the least prepared and the most impacted by storm surge.
If commercial property data had been added, those loss estimates could be even more frightening.
"Adding commercial properties into the report would increase the exposure significantly," said Botts.
NOAA NONE TOO SOON
The National Oceanic and Atmospheric Administration considered developing a hurricane category-specific storm surge scale similar to the Saffir-Simpson Hurricane Wind Scale, but NOAA scientists decided against this because, as explained above, local geographic conditions play such a strong role in storm surge.
Instead, NOAA is working to better forecast potential inundation for a given storm in its storm advisories. The administration is considering issuing Storm Surge Warnings in the next few years.
In the meantime, it is working on tools such as the probabilistic storm surge model, which can estimate surge from two to 25 feet, and Tropical Cyclone Impacts Graphics, which can illustrate the impact of the surge.
Such tools can come none too soon. AccuWeather is calling for the chance of an "extreme" hurricane season in 2010, which officially starts June 1, according to a post on the AccuWeather blog on March 14. Joe Bastardi, Chief Long-Range Meteorologist and Hurricane Forecaster, forecasts 16-18 total Atlantic storms with as many as 5 hurricane landfalls along the United States-- two to three of which could be major hurricanes. Of course, such early hurricane forecasts should be taken with as much salt as that used this winter along the Eastern Seaboard.
According to NOAA, storm-surge-induced flooding has killed more people in the United States than any other hurricane-related scourge (like high winds, tornados or fresh-water flooding).
March 30, 2010
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