Coastal-change impacts during hurricane katrina: an overview

As part of an ongoing cooperative effort between USGS, NASA and USACE, the barrier islands within the right-front quadrant of Hurricane Katrina were surveyed with airborne lidar both before and after landfall. Dauphin Island, AL was located the farthest from landfall and wave runup intermittently overtopped its central and western sections. The Gulf-side of the island experienced severe erosion, leaving the first row of houses in the sea, while the bayside accreted. In contrast, the Chandeleur Islands, LA did not experience, this classic `rollover'. Rather, the island chain was completely stripped of sand, transforming a 40-km-long sandy island chain into a discontinuous series of muddy marsh islets. Models indicate that storm surge likely submerged the entire Chandeleur Island chain, at least during the latter part of the storm. The net result was destructive coastal change for the Chandeleur Islands, while Dauphin Island tended to maintain its form through landward migration.