How Does Sea Level Rise and Storm Surge Interact?

Sea level rise increases the vulnerability of coastal areas to flooding during storms for several reasons. First, a given storm surge from a hurricane or northeaster builds on top of a higher base of water. Considering only this effect, it is estimated that development along the coast would experience a 36-58 percent increase in annual damages for a 1-foot rise in sea level, and a 102-200 percent increase for a 3-foot rise. Second, greater shoreline erosion also increases vulnerability to storms, by removing the beaches and dunes that would otherwise buffer coastal property from storm waves.

The following graphic displays historical storm water levels measured at Atlantic City projected to the year 2050 using three sea-level-rise scenarios: 1) applying historic rate; 2) applying Environmental Protection Agency (EPA) best estimate rate; and 3) applying National Research Council low estimate rate (similar to the IPCC estimate).  For example, the December '92 storm (ranked 2nd in terms of severity) had storm water levels of approximately 6.4 ft above NAVD88.  That same storm in 2050 would have water levels from 7.2 to 7.6 ft (depending on the SLR scenario). The 1944 hurricane, which was rated as a 1-in-30 year storm, when projected to 2050 would be equivalent to a 1-in-100 yr storm in severity under EPA and NRC estimated sea level rise.

Increased Risk: Estimated water levels for 2050 (source: N. Psuty June 2011)

Graphic provided by Norbert Psuty

The NJFloodMapper is not designed to predict and map specific storm surge events but can be used to examine possible flooding related to a given level of storm surge-related inundation.

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