Long-Wave Response of the West Florida Shelf to the Landfall of Hurricane Wilma, October 2005

Abstract

Direct observations of the storm surge and the subsequent long-wave response induced by Hurricane Wilma's landfall on the West Coast of Florida on 24 October 2005 are presented. The data set consists of weeklong time series of storm surge and barometric pressure measured by the U.S. Geological Survey (USGS) Florida Integrated Science Center. The survey area spanned more than 100 km alongshore from the landfall site northward. The USGS data were augmented with measurements at the National Oceanic and Atmospheric Administration tide gauge and Coastal Marine Automated Network (CMAN) stations. At the time of Wilma's arrival, the storm surge was minimal to the north of landfall site but was significant in the southern sector. Subsequently, it evolved into an edge wave pulse propagating northward as Wilma moved inland and the surge was no longer sustained by the wind forcing. The height of the wave pulse exceeded 1.5 m in detided sea level data. However, its magnitude was somewhat obscured in direct surge measurements because the wave pulse propagated during the low tide. The duration of this wave pulse was approximately 6 hours. The propagation speed of the wave front was ∼25 m s−1, while the pulse crest traveled at a lower speed of ∼10 m s−1, which indicates the dispersion effects. A relatively low phase speed suggests that the wave energy was trapped nearshore, in the water depth of 10–20 m. The wave pulse was followed by a train of weaker wavelike undulations, also propagating northward. The edge wave pulse seemed to be attenuated by a complex topography in the vicinity of Sanibel Island–Pine Island.