 The 35 miles of beaches and dunes which make up the county's 11 barrier islands provide habitat for coastal species, serve as critical storm protection for the inland communities, and form the basis of the area's thriving tourism industry.The islands are dynamic, with wave action building some islands further up, eroding others, and forming entirely new islands over time.Though hurricanes are infrequent on this part of Florida's coast, they have had a major impact on the islands, with the Hurricane of 1848 forming John's Pass between Madeira Beach and Treasure Island, a hurricane in 1921 creating Hurricane Pass and cleaving Hog Island into Honeymoon and Caladesi Islands, and 1985's Hurricane Elena sealing Dunedin Pass to join Caladesi with Clearwater Beach.