Long Island’s longest barrier island lost more than half of its beaches and dunes when it was battered by Sandy last October, according to a federal study released Tuesday.
Fire Island, which runs along the southern coast of Long Island from Babylon to Brookhaven, will be more vulnerable to future weather systems due to extensive damage wrought by last year’s historic storm, the report said.
Though damage to the island was immediately apparent -- the storm washed away 200 homes in the 32-mile island's Ocean Beach resort community -- the U.S. Geological Survey’s study is the first to quantify coastal changes the storm caused.
"The beaches and dunes of the island were severely eroded during Sandy," said Cheryl Hapke, the study's lead author.
The island, a popular summer getaway, was breached in three places during the storm, causing widespread damage to the coastal infrastructure and homes, Hapke said. The storm flattened beaches and eroded the island's 15-foot dunes extensively, according to surveys immediately after the storm.
The storm's surge pushed sand into some homeowners' living rooms last fall, but the study showed that the majority of the beaches washed away by Sandy found their way offshore.
In all, 54 percent of the island's volume of dunes and beaches were washed away. Nearly half of Fire Island's dunes were also covered with water at some point during the storm.
Damage from Sandy left Fire Island more vulnerable to winter storms. Surveys conducted over the winter showed that in some areas, the beach shifted inland by as much as 189 feet. Some spots recovered early this spring, but only 18 percent of the island’s pre-Sandy volume has returned.
"The impact from Sandy was unprecedented in recent times," Hapke said. "It is important that efforts to rebuild the island be guided by science, which shows Sandy profoundly altered the shape and position of the barrier island, shifting it landward and redistributing large amounts of sand.”
Barrier islands typically form the first line of defense against major coastal storms like Sandy.