2 Sep 2025

Coastal Hazards System–Gulf of Mexico (CHS-GoM)

Abstract: The US Army Corps of Engineers completed the South Atlantic Coastal Study (SACS) to quantify storm surge and wave hazards, expanding the Coastal Hazards System (CHS) to the South Atlantic Division (SAD) domain. The goal of CHS-SACS was to quantify coastal storm hazards for present conditions and future mean sea level fluctuation scenarios to reduce flooding risk and increase resiliency in coastal environments. CHS-SACS was completed for three regions within the SAD domain, and this report focuses on the Gulf of Mexico (CHS-GoM). This study applied the CHS’ Probabilistic Framework with Joint Probability Method Augmented by Metamodeling Prediction (JPM-AMP) to perform a probabilistic coastal hazard analysis (PCHA) of tropical cyclone (TC) and extratropical cyclone (XC) responses, including new atmospheric and hydrodynamic numerical model simulations of synthetic TCs and historical XCs. This report documents the CHS probabilistic framework for the CHS-GoM region by executing the JPM-AMP, and comprising storm climate characterization, storm sampling, storm recurrence rate estimation, marginal distributions, correlation and dependence structures of TC atmospheric-forcing parameters, development of augmented storm suites, and assignment of discrete storm weights to the synthetic TCs. Coastal hazards were quantified for annual exceedance frequencies over the range of 10 yr−1 to 10−4 yr−1.