Accession Number : ADA112788

Title :   Hurricane Impact on Gulf Coast Barriers.

Descriptive Note : Final rept. no. 2,


Personal Author(s) : Nummedal,Dag

PDF Url : ADA112788

Report Date : Jan 1982

Pagination or Media Count : 46

Abstract : Hurricane Frederic made landfall near Pascagoula, Mississippi at midnight, September 13, 1979. At the time of landfall, the central pressure had dropped to 946 mb; onshore winds in excess of 200 km/hr were lashing the Alabama coastline, and the open coast storm tide peaked at 365 cm at Gulf Shores, Alabama. Vertical aerial photography obtained in 1976 and again 9 days after Frederic made landfall, combined with multiple reconnaissance overflights and ground surveys by the authors, provided the data base for determination of shoreline erosion and the deposition of hurricane scour and sedimentary deposits. Erosion of the Gulf beach at Dauphin Island proved to follow a predictable pattern, controlled by nearshore bathymetry, whereas retreat of the shoreline of the Mississippi Sound margin was an unexpected occurrence. Apparently, this retreat was due to a hydraulic jump as washover currents entered the deep water of Mississippi Sound. Large-scale sediment redistribution on Dauphin Island proper was a consequence of the storm surge flood. The ebb surge, however, was responsible for the reopening of three inlets across Little Dauphin Island. The wave-induced property destruction on Dauphin Island was most intense immediately west of the area of high dunes. This segment of the island, the easternmost portion of the Holocene spit, has been breached twice in this century. During future storm events, breaching, or at the very least severe property destruction, in this area seems inevitable. A sensible land use plan for Dauphin Island should include a search for alternative, and potentially safer, areas for development.

Descriptors :   *Islands, *Hurricanes, Mexico Gulf, Shores, Barriers, Geomorphology, Modification, Water erosion, Sediment transport, Sea level, Reprints

Subject Categories : Meteorology
      Geology, Geochemistry and Mineralogy

Distribution Statement : APPROVED FOR PUBLIC RELEASE