Figure 4.28. Various surge zones draped over the Digital Elevation Model (DEM) for the Onslow Bay region

The Sea, Lake, and Overland Surge from Hurricanes (SLOSH) model was developed by the National Oceanic and Atmospheric Administration (NOAA) National Weather Service (NWS).  The model identifies the potential surge zones associated with the various storm categories on the Saffir-Simpson hurricane scale.  The perspective image above shows the various surge zones draped over the Digital Elevation Model (DEM) for the Onslow Bay region. 

The SLOSH model is a diagnostic model in that the hurricane's track, size, and intensity must be specified before the model is run. When these parameters are put into the model, a model wind field is produced, which in turn gives the surface stresses. The stresses act as the driving forces to move the water. Friction, the surface wind stress, and the pressure gradient cause the water to pile up along the coast.  The model repeatedly sends the theoretical hurricanes into shore at various angles of approach.  The end result is a worst-case scenario for the geographic region under study.  A maximum depth of inundation is calculated for each and every location on the map.  The output from the model is used by emergency preparedness professionals to decide who may be at risk from an approaching hurricane.

The chart below shows the results of overlaying the various surge inundation layers on the land cover classification data.  The chart displays the estimated acreage of each land cover class that may be inundated from each category hurricane based on the SLOSH model output.  This information allows planners and emergency preparedness officials to not only estimate the location of inundation areas, but also analyze the land cover and resources that may be impacted by an approaching hurricane.

Figure 4.29

The sequence of images below depicts simulated storm surge inundation areas from Category I, III, and V hurricanes draped over the Onslow Bay region DEM.  Each perspective view image is flooded up to the surge inundation level predicted by the SLOSH model.  Visualizations like the images below can be powerful educational tools for planners and preparedness officials because of the unique perspective they provide on these powerful and damaging storms. 

Hurricane Category I Storm Surge

Figure 4.30
 

Hurricane Category III Storm Surge

Figure 4.31
 

Hurricane Category V Storm Surge

Figure 4.32