Assessment of Caribbean Coastal Hazard Posed by Tropical Cyclones

Abstract This research provides a comprehensive assessment of the compound hazards to the Caribbean from wind and storm surge posed by tropical cyclones (TCs) under the recent historical climate, integrating the Columbia Hazard model (CHAZ) for TC characteristics with the GeoClaw storm surge simulation model. A large set of synthetic storms, generated by downscaling an observation-based reanalysis using CHAZ, is used to drive GeoClaw so that return period curves for both wind and surge can be generated at a large set of locations across the Caribbean. The analysis reveals that the northern Caribbean islands, particularly the Bahamas and western Cuba, are subject to greater TC-related wind and surge hazards than the eastern Caribbean islands, such as St. Lucia and St. Vincent. This discrepancy is attributed both to the higher frequency of high-intensity TCs and to shallower bathymetry in the northern Caribbean. The relationship between peak wind and peak surge values across the storm set is both nonlinear and relatively weak, although the largest surges do not occur with the weakest storms. The complexity of the wind–surge relationship reflects the region’s varying bathymetry and the roles of multiple storm characteristics, such as storm size and track, in determining storm surge. Significance Statement This study advances understanding of tropical-cyclone-induced wind and storm surge hazards and their impacts on Caribbean islands. By integrating the Columbia Hazard model (CHAZ) for tropical cyclones with the GeoClaw numerical storm surge model, we provide a detailed assessment of regional variations in hazard, particularly highlighting the heightened threats faced by the northern Caribbean. These insights are critical for enhancing coastal resilience, informing regional disaster preparedness strategies, and guiding policy development. Additionally, the findings establish a baseline for future research exploring the exacerbating effects of climate change on combined cyclonic hazards.