Investigation of Storm Surge Impacts from Hurricane Irma Along Coastal Areas of Southern Mainland Florida

The 2017 Atlantic Hurricane season was one of the most active since the 1850s. The tenth tropical cyclone of the season, Major Hurricane Irma, had peak winds of 185 mph as it approached the Leeward Islands of the Caribbean, making it the strongest Atlantic storm outside of the Gulf of Mexico and the Caribbean Sea on record. During its most intense phase, Irma was recognized as a significant threat to South Florida. Irma weakened to a category three hurricane before making its second U.S. mainland landfall at Marco Island on the southwest Gulf coast of the Florida Peninsula. Due to expected life-threatening storm surge impacts, a Storm Surge Warning was issued for all coastal areas of South Florida, in addition to the traditional wind-based Hurricane Warning. Hurricane Wilma of 2005 was the last major hurricane landfall along the Florida Peninsula, at which time Storm Surge Warnings were not in use.

This study focuses on the surge-related damage that occurred with Irma in the coastal areas of Palm Beach, Broward, Miami-Dade, Mainland Monroe, and Collier Counties in Florida. It includes a comparison of high water marks along coastal areas affected by storm surge to the storm surge forecast and related warnings. Comprehensive surveys across the highly density urbanized coastal areas of South Florida a few days after Hurricane Irma made landfall identified the hardest hit areas across the region and provided the data for this investigation.