Coastal Storm Surge Scenarios for Water Utilities

This map illustrates hurricane strike frequency and worst-case coastal storm surge inundation scenarios derived from:

  • National Hurricane Center’s hurricane strike dataset
  • Federal Emergency Management Agency's 100-year and 500-year flood plains
  • National Oceanic and Atmospheric Administration's Sea, Lake, and Overland Surge from Hurricanes (SLOSH) model

The National Hurricane Center (NHC) maintains a hurricane strike dataset (xlxs)(20 pp, 301 K) for U.S. coastal counties, including direct and indirect strikes from different hurricane categories during 1900-2009 (last updated February 4, 2010).

Analytical methods and assumptions differ between the approaches used to develop the Federal Emergency Management Agency (FEMA) flood plain and the SLOSH model maps. The FEMA flood plain maps focus on riverine and coastal flooding, while the SLOSH model map focuses on storm surge inundation (defined as the abnormal rise of water generated by a storm, over and above the predicted astronomical tides).  Get a detailed explanation of the differences in approach (PDF)(5 pp, About PDF)

How do I access storm surge inundation data?

  1. Double click on the map to zoom in to your location of interest or type a location into the search field to the right of the map toolbar.
  2. Use the check boxes on the right to toggle the different SLOSH layers on/off.

Please note the home screen only displays the SLOSH and hurricane frequency layers. The FEMA flood plains are only visible at detailed zoom levels and will appear on the legend once the appropriate zoom level has been reached. The SLOSH layer is visible in a range from the national view to a county view and will not appear past a lower zoom level. The SLOSH layer will disappear from the legend once the user reaches too detailed a zoom level.