Hurricane season brings threat of beach erosion

9:59 AM, May 31, 2013   |    comments
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Florida is known for its beautiful beaches, but the 2013 hurricane season brings the threat of beach erosion. Even weak storms can be more devastating than intense hurricanes.

In 2012, Hurricane Sandy came ashore with winds almost half the speed of Hurricane Charley in 2004, yet the storm surge was twice as big.  And last year, Tropical Storm Debby damaged the coastline along Tampa Bay, making it more vulnerable to storms this season.

Debby flooded parts of Bayshore Boulevard in Tampa with a minimum storm surge of three to four feet.  The last significant storm surge seen in the Bay Area was in 1921 when a category three hurricane hit Tarpon Springs.   An 11-foot surge put ships on land and leveled buildings.  Since then, the largest hurricane surge came 28 years ago with hurricane Elena, which raising the Gulf six feet along the Gulf.

Different kinds of beaches offer different kind of protection to the coastline.  The bigger the sand dune, the healthier the beach.  You can think of the dunes as the coast's first line of defense from storm surge.  They almost serve as a speed bump--slowing the waves down and keeping more sand on the beach.

Last year, Tropical Storm Debby eroded many of the beaches along Pinellas County.  It may have been a weak storm, but it sat along the coast for days--chiseling away at the dunes at places like Sunset Beach, the worst spot for erosion in Pinellas County.

The U.S. Geological Survey in St. Petersburg has been been trying to predict which sections of the coastline will erode worse than others.  Computer programs figure out how much of the shoreline will change by factoring in coastal elevations, wave forecast and potential storm surge.  Those programs accurately predicted vulnerable areas in the path of Superstorm Sandy last year.  The same tools can be used to find weak areas in Tampa Bay.

"Along the entire stretch of coast, we experience dune erosion," said Dr. Hilary Stockdon of the USGS.  But she says areas around Fort De Soto park are more vulnerable. "That's because the dunes are so low there. So low in fact, that they experience overwash which is when the waves actually overtop the island and bring sand inland."

This year, meteorologists with the National Weather Service in Ruskin will test new storm surge warning products. It would be independent of a hurricane warning and could be issued even if a storm isn't heading our way.  

"We're all familiary with hurricane warnings," said Dan Noah, the Warning Coordination Meteorologist in Ruskin. "But sometimes the impact from that hurricane are well away from that hurricane. We saw that with Dennis a few years back.  The hurricane warning for the wind was along the Panhandle. However we had above-normal surge all the way up the west coast of Florida into the Big Bend area and that's where a storm surge warning in the future could be outside of the hurricane warning even if the skies are sunny."