Coastal Change Hazards Team Forecasted Hurricane Sally Beach Impacts

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Prior to landfall on September 16, 2020, the Coastal Change Hazards Team forecast that 57 percent of Mississippi’s barrier island beaches were very likely to erode at the dunes’ base. In addition, 34 percent of dunes were forecast to be very likely to be overwashed by storm waves and 4 percent of the dunes were forecast to be inundated. In Alabama, 32 percent of beaches were very likely to erode at the dunes’ base, 3 percent of dunes were forecast to be very likely to be overwashed by storm waves and none of the dunes were forecast to be inundated. In eastern Louisiana, 10 percent of beaches were very likely to erode at the dunes’ base, 14 percent of dunes were forecast to be very likely to be overwashed by storm waves and 2 percent of the dunes were forecast to be inundated. Along the Florida Panhandle, 1 percent of beaches were very likely to erode at the dunes’ base, less than 1 percent of dunes were forecast to be very likely to be overwashed by storm waves and none of the dunes were forecast to be inundated. In addition to informing the public, forecasts were used to determine placement of sensors for USGS real-time response to Hurricane Sally. After landfall of a storm, the Coastal Change Hazards team uses NOAA imagery, USGS CoastCams, other beach cams, Digital Elevation Models (DEMs) constructed from post-storm aerial imagery and lidar data, and observations from USGS sensors to validate forecasts.

The USGS Coastal Change Forecast model is used to estimate the impacts of elevated waves and storm surge along the coast due to extreme storms. This model has been in use since 2011 and is continually improved. To view a geonarrative about USGS tools to forecast coastal change, visit Real-time Forecasts of Coastal Change.