It is common to see surge maps displayed on web sites or printed in local hurricane planning brochures. A surge map can provide you a great deal of information if you understand how they were prepared and what they are intended to be used for.

Surge maps are based upon the SLOSH model and is the basis for the "hazard analysis" portion of coastal hurricane evacuation plans. Hundreds of hypothetical hurricanes are simulated with various Saffir-Simpson categories, forward speeds, landfall directions, and landfall locations. An envelope of high water containing the maximum value a grid cell attains is generated at the end of each model run. These envelopes are combined by the NHC into various composites which depict the possible flooding. One useful composite is the MEOW (Maximum Envelopes of Water) which incorporates all the envelopes for a particular category, speed, and landfall direction. Another composite that is useful to emergency managers is the MOM (Maximum of the MEOW's), which combines all the MEOWs of a particular category.

To provide some tools to emergency managers, regional evacuation studies have been completed using the SLOSH models. The MEOW maps are produced for all five levels of hurricane intensity and for many direction of storm motion, and they depict the "worse case" scenario for all categories of storms and all potential storm tracks. MEOW maps are just one tool an emergency manager will use to determine risk areas and evacuation recommendations.

To develop the MEOW for the Chesapeake Bay basin, the following SLOSH model simulations were run:

From this data, a storm surge map for Hampton was created. This MOM (Maximum of MEOWs) map depicts the "worst of the worst", as it does not depict the results of any one storm. The data that is depicted on the map is from the above table, where the SLOSH runs would create a storm surge that would affect Hampton.

The storm indicators (boxes) show the depth of water calculated by the SLOSH program. Notice that there are no surge heights for Category Five storms. The general location of Hampton Roads area is not conducive to storms of that intensity.

It is important to understand about storm surge, and to have an evacuation plan should it be necessary.