An Analysis of Hurricane Irma's Winds in South Florida

Hurricane Irma struck South Florida on September 10, 2017 and caused significant damage to structures and trees as well as widespread power loss. Irma caused more than personal inconvenience to most South Floridians and its aftermath left people wondering how they can be better prepared in the future for the next hurricane. From a wind impact perspective, it is important to spatially quantify the wind magnitude so that residents and business owners of South Florida can attain a better understanding of the maximum wind speeds experienced in their neighborhood during Irma.

In this study, Hurricane Irma’s winds are analyzed across the National Weather Service Miami County Warning Area, which includes the Florida Peninsula from Lake Okeechobee southward and adjacent coastal waters of the Gulf of Mexico and Atlantic Ocean. All available data from surface-based weather stations and anemometers are incorporated. WSR-88D Doppler velocity data are also analyzed and used to fill in the gaps for locations where observations are sparse. These data are further augmented with results of ground wind damage surveys. Detailed, color-contoured maps of sustained winds and gusts will be provided in addition to a list of observations. For the purposes of consistency on the color-contoured map, all sustained wind observations are converted to a 10 meter, one minute average using standard conversion metrics. Preliminary results indicate that sustained hurricane force winds up to Category 2 strength on the Saffir-Simpson Hurricane Wind Scale with higher gusts occurred in portions of coastal Collier County, including the Naples area. In the east coast metropolitan areas of Miami, Fort Lauderdale, and West Palm Beach, most areas received sustained strong tropical storm force winds between 50-73 mph with hurricane force gusts of 74 mph or greater.