Second, due to longshore drift, the barrier island sort of roll lengthwise, causing inlet migration, and the building of sand bars, spits, baymouth bars, and other soft features. Humans alter some of these effects by building on barrier islands. read more
While barrier islands can be built up by the action of waves and currents, they can also easily be taken away by waves and currents, given a change in direction, which can be caused by too much buildup. The currents blocked their own normal path. Barrier islands are also the first to be attacked if a storm comes up. read more
In the United States, barrier islands occur offshore where gently sloping sandy coastlines, as opposed to rocky coastlines, exist. Consequently, most barrier islands are found along the Gulf Coast and the Atlantic Coast as far north as Long Island, New York. read more