Cape Cod Hurricane Category 3 Flood Model

By John Gravelin, Linnean Solution

Image Courtesy of  John Gravelin, Linnean Solutions

This image of Cape Cod represents a Category 3 Hurricane flood model under ‘perfect’ storm conditions during an average (mean) tide. The flood layer was obtained from the National Oceanic and Atmospheric Administration (NOAA) Hurricane Research Division Atlantic Oceanographic & Meteorological Laboratory. The hurricane model is referred to as Sea, Lake and Overland Surges from Hurricanes (SLOSH).

The SLOSH models account for several variables of hurricanes, including the intensity of a storm, forward speed, storm trajectory, and initial tide levels based on observations from previous events. NOAA runs several hundred hurricane models over an area like New England and develops a ‘Maximum Envelope of Water’ or a baseline of flooding per hurricane category. NOAA also provides a flood model that represents “the worst case scenario for a given category of storm under ‘perfect’ storm conditions,” and takes the maximum of the variables above.

This image of Cape Cod represents the maximum flood damage possible under ‘perfect’ storm conditions. Areas in dark blue are most susceptible to flooding (particularly along the southeastern and northern shoreline of the Cape) and areas of light blue are least susceptible (seen around the southwestern part of the Cape towards Rhode Island). Even the least susceptible areas are vulnerable to flooding under certain storm conditions, and proper planning should consider ways to mitigate damage.

For more on how the NOAA calculates hurricane flooding, see “How is storm surge forecast at NHC.” National Oceanic and Atmospheric Administration (NOAA) Hurricane Research Division Atlantic Oceanographic & Meteorological Laboratory.http://www.aoml.noaa.gov/hrd/tcfaq/F7.html

For more on historic storms and paths see “Historical Hurricane Tracks.” National Oceanic and Atmospheric Administration. http://csc.noaa.gov/hurricanes/

(Excerpted from the USGBC MA August 2013 Newsletter)