Experts predict erosion at a third of Virginia’s beaches from Dorian

Virginia Beach. (Creative Commons via Pixabay)

Experts predict more than a third of Virginia’s beaches and dunes will see “some level of erosion” from Hurricane Dorian, the U.S. Geological Survey said Friday.

Virginia will be much harder hit than Maryland, with about 34 percent of the commonwealth’s dunes experiencing erosion compared to only 2 percent in its northern neighbor, the agency says.

“The bases of Maryland and Delaware dunes sit higher above ocean levels than the base of Virginia dunes,” said research oceanographer Kara Doran, who leads the USGS’ Coastal Change Hazards Storm Team. “Additionally, the Maryland and Delaware dunes are also generally taller than Virginia dunes. This is important, because the increased elevation of the base of the dunes reduces the amount of time strong waves and surge can impact and erode them, and the taller height of the dunes requires higher surge levels before they are overtopped.”

The agency also says about 6 percent of Virginia beaches are “very likely” to experience overwash — when waves and storm surge exceed the tops of sand dunes, pushing sand inland.

The storm predictions are based on the survey’s eight year old Coastal Change Forecast model, which uses National Hurricane Center storm-surge predictions and the National Oceanic and Atmospheric Administration’s wave forecast combined with beach slope and dune height data to predict how waves and storm surge will affect beaches.

A real-time map is available at the USGS’ Coastal Change Hazards Portal. The forecast helps local and state officials flag places where storm surge might be the most severe, informing decisions on evacuations and where to place equipment, the USGS says.

Emergency managers can use the coastal change forecast to help identify locations where coastal impacts might be the most severe and this data can assist them as they make critical decisions on which areas to evacuate, which roads to use, and where to position heavy equipment for post-storm clean-up.

As of 2 p.m., Dorian was about 125 northeast of Capt Hatteras, North Carolina, and heading out to sea with maximum sustained winds of 90 miles per hour, according to the NHC. Hampton Roads remains under a storm surge warning.