Chandeleur Islands, 2001-2005

The islands have been generally shrinking and migrating landward since the late 1800s. A survey in the 1980s estimated that they would be in existence for about three more centuries. Before 1996, the seaward front of the islands lost about 20-30 feet of land each year, mostly replaced at the rear. From 1996 to 2004, the loss rate grew to about 300 feet (91 m) per year. In 1998, Hurricane Georges destroyed the islands and left the lighthouse in the middle of the ocean, and the barrier islands only just recovered when Hurricane Katrina struck in 2005. However, the combined effect of Hurricane Dennis and Hurricane Katrina in 2005 reduced the island to shoals or sub-surface formations, and toppled the Chandeleur Island Lighthouse. Powerful storms can produce changes that would otherwise have taken many years. A study released in 2006 by geologists from the University of New Orleans shows that the usual sand and sediment patterns that rebuilt the islands after big storms have not been restored since Katrina reworked the area. There is also evidence of unprecedented landslides on the seafloor on the side toward the Gulf of Mexico, potentially allowing stronger waves with greater erosional impact to reach the islands. If the islands recover, it may take generations. If movements of sand and sediment do not restore the islands, they may be gone in a decade. (Chandeleur Islands)

Over 100 Years of Land Change for Coastal Louisiana Including Hurricane Assessments of 2005