what is a barrier island?
What are barrier islands? Barrier islands are long, relatively narrow islands that run along a coast parallel to the mainland. They are built up by the action of waves and currents and help protect the coastline from erosion by surf and tidal surges. Barrier islands occur all over the world but are especially prevalent along the Atlantic and Gulf coast of North America. This figure from the USGS shows the major parts of the typical barrier island system. Open Water - Barrier Islands are found in areas where the sea floor slopes away gently to the continental shelf. The shallow angle of incoming waves makes it very easy to transport sediments in and out with waves, tides, and storms.