A Major Hurricane in Miami Would Cause Billions in Losses, New Report Says

Most Miamians can never quite seem to get around to purchasing that pesky flood insurance for their house or apartment. Try as they might to put it on a to-do list, dishing out the bucks for a weather event that never seems to happen inevitably gets eclipsed by other tasks.

Well, as if you needed another reminder: Florida is incredibly hurricane prone. And flooding from a major hurricane here will most likely be disastrous.

Even though Florida has not had a major storm surge for decades, a new report by disaster insurance agency Karen Clark and Co. says Florida is home to four of the 10 U.S. cities most vulnerable to flooding. And Miami, where there’s a high likelihood of a severe Category 5 storm, is number four on the list.

According to the report, which is based on innovative risk modeling, Miami’s vulnerability stems from “the sheer magnitude of property values near the coast along with low coastal elevations.”

Hurricane Katrina and Superstorm Sandy showed just how much havoc storm surge flooding can wreck, and suggested that more robust models are needed to assess risk. So KCC developed and released an advanced model earlier this year and used it to conduct the study.

Storm surge, defined as “the rise in sea surface along the coast caused by a tropical cyclone,” depends on a number of factors, including things like ocean floor topography and storm pressure. That’s why small storms can end up causing huge floods, and big storms can end up causing little ones. To measure impact on a variety of points, Clark and her colleagues used a high resolution coastal flooding model with detailed databases of property exposures. 

They used the “hundred year hurricane” measure — the really severe event that only runs a one percent probability of happening in a year. Because probability is one percent, it’s expected to occur once every 100 years on average. In Miami, the 100 year hurricane is a strong Category 5 storm with peak winds of 165 miles per hour.

Cities were then ranked by the estimated property damage, including building losses. Coming in at number one, Tampa/St. Petersburg is the metropolitan area most vulnerable to flooding damage with a loss potential of $175 billion. Next were New Orleans, New York City, Miami and Fort Myers.

Miami hasn’t had a direct hit by a major storm since the Great Miami Hurricane of 1926. And the past two Category 4 storms to make landfall in Florida — Andrew and Charley — did not produce much storm surge. But should the big one hit, the estimated property damage and loss from storm surge in Miami could total $80 billion, the report says. KCC estimates that a 1926-force hurricane today in Miami would cause over $200 billion in losses, including from wind and storm surge damage.

"In general, potential property losses have been doubling every 10 years for the past several decades due to increases in the numbers, sizes, and values of properties constructed along the coast in Southeast Florida," Karen Clark told New Times.

Interestingly enough, the report says it's not Miami’s physical features that make it especially vulnerable. In fact, the city’s coastal features are actually less favorable to storm surge than many other coastal areas. That's because our “continental shelf falls off very steeply and the coastline is relatively free of significant bays or other features that would create channeling effects,” it says. 

For us, the damage really comes from all the property we’ve got where a surge is likely to swell. 
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Jessica Weiss