Selection of hazard-consistent hurricane scenarios for regional combined hurricane wind and flood loss estimation

Abstract

This paper presents a new methodology for selecting hazard-consistent hurricane scenarios (with similar return periods) for estimating the regional losses due to combined hurricane wind and flood. An in-house stochastic hurricane simulation program was used to simulate 50,000 years of full-track synthetic hurricanes. A wind field model along with a boundary layer model was utilized to compute the surface wind speeds. As illustrative examples, the SLOSH (Sea, Lake, and Overland Surges from Hurricanes) model was employed to calculate the corresponding flood elevations for two loss estimation domains (Charleston Peninsula, South Carolina and Miami Beach, Florida) with each of them divided into census blocks. The peak wind speeds and maximum flood elevations at the centroids of respective census blocks were utilized to determine the joint mean recurrence intervals (MRIs) of individual hurricane events. For regional loss estimation purpose, the joint MRIs of hurricanes were weighted by the population of every census block. A hurricane selection procedure was developed to select hazard-consistent hurricane scenarios with a joint MRI of 100 years. Three hurricane ensembles, selected based on only wind speeds, only flood elevations, and joint wind speeds and flood elevations, were imported into the HAZUS-MH (Hazards US Multi-Hazards) program to perform combined wind and flood loss estimations. The results indicate that hurricane selection using either only wind speeds or only flood elevations can overestimate the combined losses. The different characteristics of the selected hurricane scenarios for the two loss estimation domains are also discussed.