Sea, Lake, Overland, Surge from Hurricanes

("SLOSH" Model)


The greatest potential for loss of life related to a hurricane is from storm surge. It is imperative for emergency managers to understand storm surge vulnerability, potential threat, and who should evacuate for specific storm threats.

SLOSH, which stands for Sea, Lake, and Overland Surge from Hurricanes, is a computerized model developed by the Federal Emergency Management Agency (FEMA), United States Army Corps of Engineers (USACE), and the National Weather Service (NWS) to estimate storm surge depths resulting from historical, hypothetical, or predicted hurricanes by taking into account a storm's pressure, size, forward speed, forecast track, wind speeds, and topographical data.

SLOSH is used to evaluate the threat from storm surge, and Emergency managers use this data to determine which areas must be evacuated. SLOSH output is used by the National Hurricane Program (NHP) when conducting Hurricane Evacuation Studies as a hazard analysis tool for assisting with the creation of state and local hurricane evacuation plans or zones. SLOSH model results are combined with roadway network and traffic flow information, rainfall amounts, river flow, or wind-driven waves to determine a final analysis of at-risk areas. Storm surge also can affect rivers and inland lakes, potentially increasing the area that must be evacuated.

The point of a hurricane's landfall is crucial to determining which areas will be inundated by the storm surge. Where the hurricane forecast track is inaccurate, SLOSH model results will be inaccurate. The SLOSH model, therefore, is best used for defining the potential maximum surge for a location.

If you have a Hurricane Evacuation Study, you do not need information about storm surge depths in a real hurricane situation. You will only need to know the forecast of the storm's intensity at landfall and the corresponding evacuation zones in order to make an appropriate evacuation decision.

SLOSH Display Training for Emergency Managers

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Last Modified: Thursday, 31-Jul-2008 16:21:32 EDT