Regional Overwash from Hurricanes Frances-Jeanne and Ivan

Marianne O'Neal Caldwell, Ping Wang, Mark Horwitz, James Kirby, and Swagata Guha
Coastal Research Laboratory, Department of Geology, University of South Florida, Tampa, Florida 33620

Four strong hurricanes impacted a large portion of Florida coast within a month during the summer of 2004. Hurricane Ivan impacted nearly the entire Florida panhandle coast causing tremendous overwash deposits. Hurricanes Frances and Jeanne, impacting nearly the same location along south Florida Atlantic coast, also resulted in substantial overwash deposits. Overwash from Hurricane Charley is limited. This study compares the overwash deposits from Hurricanes Frances-Jeanne and Ivan. The overwash deposits from Frances and Jeanne are relatively restricted in aerial extent, being localized north of the eye and mostly within 30 km. In contrast, overwash deposits from Ivan are far more extensive, stretching over 120 km from the eye. Over-wash from France-Jeanne typically transgressed into the backbarrier mangrove swamp and displays a tongue shape. The shape and extent of the overwash fans/tongues are influenced by the vegetation density. The extensive overwash from Hurricane Ivan typically does not display an overall fan shape. The different overwash extents and sedimentological characteristics are influenced by both hurricane intensity and pre-storm morphology, particularly the latter for this case.

AAPG Search and Discovery Article #90080©2005 GCAGS 55th Annual Convention, New Orleans, Louisiana