Insurance industry research firm CoreLogic has released a second annual study of the storm surge flooding risk to highly populated coastal areas. Like last year’s study, this year’s edition, “ 2011 CoreLogic® Storm Surge Report : Residential Storm-Surge Exposure Estimates for 10 U.S. Cities,” zeroes in on heavily built-up population centers — coastal cities where the potential dollar value of losses that could occur in a worst-case hurricane landfall scenario are huge. But this year’s report also goes a step farther than last year’s, comparing the footprint of properties vulnerable to a possible flood against the flood zone database maintained by the Federal Emergency Management Agency (FEMA). The study’s conclusion will come as no surprise to anyone who has taken a close look at FEMA’s flood zones: many, if not most, of the coastal properties that could be damaged or destroyed by storm surge flooding in a major hurricane lie outside of FEMA’s official flood zone, and are likely to be uninsured. Above, CoreLogic’s graphical representation of the storm surge risk to the Charleston, S.C., area. Red zones are most likely to be hit by a storm surge flood; higher elevations represent a greater property dollar value. Interestingly, the greatest potential economic loss from a really bad hurricane isn’t found in Florida or on the shores of the Gulf of Mexico, but in the high-value, heavily built-up shoreline of Long Island, N.Y. (which includes Brooklyn). CoreLogic reports, “The findings show that of the ten metro areas studied, Long Island has the most residential property at risk with $99 billion of exposure, followed by the Miami-Palm Beach region with $44.9 billion of exposure and Virginia Beach with $44.6 billion of exposure. The metro areas identified as having the lowest economic risk are Mobile, Ala. with $3 billion of exposure and Corpus Christi, Tex. with $4.7 billion. Among the densely populated coastal regions with the highest number of individual properties at risk are Virginia Beach, with nearly 289,000 properties, New Orleans, with more than 278,000 properties and Tampa, with more than 277,000 properties at risk.” These are worst case numbers, of course, and the odds are strongly against the worst case occurring in even one location, much less in all ten cities in a single year. But that all depends on the weather. Hurricane forecasters have already begun to predict the intensity of the 2011 season, and this year, they say, is shaping up to be a bad one. Colorado State University researchers say conditions favor the formation of nine hurricanes this year in the Atlantic basin, including five major hurricanes (“ Colorado State University Forecasters Predict AboveAverage 2011 Atlantic Hurricane Season ”). Last year’s hurricane season fizzled — at least if we’re talking about hurricanes that strike land. Despite predictions of a heavy season, 2010 was the fifth year in a row that no major hurricane made landfall in the U.S. (“ Hurricane Season Slides By And the U S Dodges the Bullet ). That good luck was brought about by what researcher Jeff Masters called “friendly steering currents” — an established jet stream pattern in 2010 that tended to curve storms into the north Atlantic, rather than permit them to push on towards the U.S. mainland. But 2010 also saw the unusual occurrence of a Category 1 hurricane striking the province of Newfoundland, Canada. So while the steering currents did push almost every storm out to sea, they pushed that one storm into land on a far more northerly track than is typical. So if the steering currents Masters described happen to be in force in 2011 — but not quite as strongly — this year’s hurricanes could very well curve north just far enough to hit some of the high-value targets mentioned in the CoreLogic report: New York’s Long Island suburbs, Tidewater Virginia, or Charleston. There’s no way to predict that, of course. Under the circumstances, it’s probably wisest to heed the advice of Colorado State’s Phil Klotzbach: “It is recommended that all vulnerable coastal residents make the same hurricane preparations every year, regardless of how active or inactive the seasonal forecast is. It takes only one landfall event near you to make this an active season.”
