Carolina Environmental Diversity Explorations

Hurricanes on sandy shorelines · By Dirk Frankenberg

Dune erosion on Oak Island (1)

dunes and houses with structural damage

Figure 8. Houses on Oak Island damaged by Hurricane Floyd. (Photograph by the author. More about the photograph)

Shoreface construction on southeastern barrier islands rarely fares well when hurricanes make landfall over them. Figure 8 shows how this generalization played out on Oak Island during Hurricane Floyd. The houses were behind a small primary dune before the hurricanes. That dune was flattened and its sand was moved both landward and seaward. The sand that moved landward formed overwash fans that we will see later. The sand that moved seaward formed offshore sand bars that have already begun to contribute sand to the beach. The natural process of offshore sand being added to coastline beaches is called beach accretion. We will soon see evidence of its having happened on Oak Island.

Definitions

barrier island n.
A long, relatively narrow island running parallel to the mainland, built up by the action of waves and currents and serving to protect the coast from erosion by surf and tidal surges.
hurricane n.
A severe tropical cyclone originating in the equatorial regions of the Atlantic Ocean or Caribbean Sea or eastern regions of the Pacific Ocean, traveling north, northwest, or northeast from its point of origin, and usually involving heavy rains and has surface wind speeds greater than 74 miles (or 119 kilometers) per hour. [more]
dune n.
A hill or ridge of wind-blown sand.
beach accretion n.
Accumulation of sand or other beach material due to the natural action of waves, currents and wind; a build-up of sand or other beach material.
accretion n.
A slow addition to land by deposition of water-borne sediment; an increase of land along the shores of a body of water.