SLOSH model verification: a GIS-based approach

Contingent with the National Oceanic and Atmospheric Administration (NOAA) 10-year strategic plan for storm surge operations, this study proposes a standard methodology for the verification of the Sea, Lake, and Over-land Surge from Hurricanes (SLOSH) model. In order to prescribe future enhancements to the SLOSH model and National Hurricane Center (NHC) operations, a comprehensive validation technique must be developed, tested, and implemented. To aid in this endeavor, water level observations from 3 federal agencies (NOAA, Federal Emergency Management Association, and United States Geological Survey) were compiled for five major hurricanes: Gustav, Ike, Katrina, Rita, and Wilma. This comprehensive dataset was converted to the necessary vertical datum for application at the NHC, and the entire data set was converted into ArcGIS format facilitating the development of an objective methodology for computing verification statistics. Collectively, these accomplishments represent the most comprehensive effort to-date to develop a standardized and objective methodology at the NHC for verifying SLOSH-generated forecast products. As an application of the new verification methodology, this study investigates the performance of the SLOSH Maximum Envelope of Water (MEOW) product during Hurricane Ike. While the MEOW product is heavily used by the NHC, emergency management community, and other federal agencies to assess potential storm surge vulnerability, these products have never been validated against water level observations. This study presents verification results on the overall accuracy of the SLOSH MEOW with emphasis on its application as a forecast tool during the days leading up to landfall. This research is supported by the NOAA Office of Education Ernest F. Hollings Scholarship.