Impacts of Hurricane Irma on the Circulation and Transport in Florida Bay and the Charlotte Harbor Estuary

Hurricane Irma impacted the coastal ocean and estuaries of west Florida as it transited the Florida peninsula from 10 to 12 September 2017, after making landfall first at Cudjoe Key as a Category 4 hurricane and then again at Naples, as a Category 2 hurricane. The response to Hurricane Irma is analyzed using both in situ data and a hindcast simulation by the West Florida Coastal Ocean Model (WFCOM). During the Irma passage, a negative storm surge followed by a positive surge occurred along the west Florida coast, with a recorded water level fluctuation of 3.31 m (from trough to peak) within Rookery Bay, and the negative surge with sea level set-downs (> 1 m) caused drying in Florida Bay and the Charlotte Harbor estuary. Irma-driven currents in Florida Bay, estimated to be 1.50–2.00 m/s, were strong enough to damage benthic communities. The resulting ocean circulation patterns and water exchange pathways are revealed by simulated Lagrangian trajectories. Also investigated is the memory of the coastal system. Whereas sea level and currents restored back to their normal fluctuations within a day, water temperature and salinity required several days to stabilize, and by virtue of heavy rainfall, excess freshwater input from rivers resulted in lower estuarine and nearshore salinities that lasted for several weeks.