On the ocean side the surf beats the sand beach, the waves arriving rhythmically, sometimes roughly, rolling in, unobstructed, across thousands of miles of open ocean. The longest and most extensive chain of barrier islands in the world lines the eastern shore of North America. From New York to Florida to Texas, the islands fringe the continent, tucked in close to the mainland or standing off across miles of bay. A barrier island is low and sandy, swept by winds. A dune forms when windblown sand collects around clumps of salt-resistant American beach grass.
Dunes protect against storm tides.
Without them, the sea will wash across the island, cutting new inlets and chewing away the shore. Under normal conditions, a barrier beach loses some of its sand to winter storms, but the sand is replenished from offshore bars the following summer. A barrier island can be a place of extremes, baking hot in summer, frigid in winter, swept by the wind in all seasons. Still, life abounds. Other life forms are more furtive.