Definition - What does Barrier Islands mean?
Barrier islands are deposits of sand and sediment that follow the coastline and are only separated from the mainland by shallow waters. The East Coast and the Gulf of Mexico have chains of these barrier islands, protecting the coast from wind and waves and absorbing storm energy. Barrier islands are the coast’s defence against storms and form marine habitats that support a huge diversity of wildlife.
Safeopedia explains Barrier Islands
Barrier islands consist of a number of different zones, namely: salt marsh on the landward side of barrier islands, barrier flats that are often flooded during high tides, dunes that are usually only flooded during storms, and beaches on the side of the barrier islands facing the sea. The integrity of barrier islands is essential to protecting mainland areas, such as seen in coastal Louisiana, from storm surges that would otherwise rapidly erode coastlines.