Saturday, October 27, 2012

Sandy to erode many Atlantic beaches

US Geological Survey: Nearly three quarters of the coast along the Delmarva Peninsula is very likely to experience beach and dune erosion as Hurricane Sandy makes landfall, while overwash is expected along nearly half of the shoreline. The predictions of coastal change for the Delaware, Maryland and Virginia peninsula is part of a larger assessment of probable coastal change released by the U.S. Geological Survey Friday.

"Model forecasts are run anew for each hurricane, as each case has unique factors in terms of storm intensity, timing with respect to tides, angle of approach, and must account for ever-changing details of coastal dune configuration," said USGS Director Marcia McNutt. "These models help us understand where emergency management resources might be most needed." Overwash, the landward movement of large volumes of sand from overtopped dunes, is forecasted for portions of the east coast with the projected landfall of the storm. The severity of overwash depends on the strength of the storm, the height of the dunes, and how direct a hit the coast takes.

 “On the Delmarva Peninsula, near the storm's expected landfall, close to three quarters of the sandy coast is expected to see beach and dune erosion. Fifteen percent of the coast is very likely to be inundated by waves and storm surge,” said USGS Oceanographer Hilary Stockdon from the USGS St. Petersburg Coastal and Marine Science Center. In these areas, waves and storm surge would transport large amounts of sand across coastal environments, depositing sand both inland and offshore and causing significant changes to the landscape, Stockdon noted.

The models show that along the New Jersey shore, 81 percent of the coast is very likely to experience beach and dune erosion, while 7 percent is very likely to experience overwash. It also indicates that on the south shore of Long Island, N.Y., including Fire Island National Seashore, 43 percent of the coast is very likely to experience beach and dune erosion. Overwash and inundation are not expected in these areas because of the relative high dune elevations.... 

Quogue, NY, January 21, 2010 -- Severe beach erosion and damage on Long Island's South Shore is the result of the November nor'easter. Photo by Ed Edahl for FEMA

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