Compound Flooding from Cyclones in Coastal Regions of the Southeastern United States

The Southeastern United States (SEUS) has experienced devastating tropical cyclones that pose serious threats to coastal communities due to the simultaneous impact of multiple flood drivers. While extreme rainfall can overwhelm drainage systems, storm surge driven by high winds can further intensify coastal flooding. Traditional flood risk assessments and infrastructure design often consider these drivers in isolation, overlooking their combined effects. This study investigates the cooccurrence of compound flood events in the SEUS by integrating storm tide data from 18 NOAA tide gauges along the Gulf and Atlantic coasts with corresponding precipitation data. Using statistical dependence analysis, we show that compound flood hazards are more likely at many of these locations due to strong interactions between storm tide and precipitation. We estimated joint return periods for tropical cyclone events, revealing substantial variation across different storms and geographic locations. Our results highlight the importance of incorporating compound flood drivers into coastal floodplain planning, infrastructure design, and mitigation strategies to better prepare for future climate-driven extremes.