Geomorphic recovery of the Chandeleur Islands, Louisiana, after a major hurricane
Kahn, Jacob H
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The processes of geomorphic change in the Chandeleur Islands, Louisiana, were monitored for two years after the passage of Hurricane Frederic in September 1979. Rates of beach accretion and hurricane-channel closure on these transgressive, microtidal barrier islands were affected by subsequent storms, including major frontal passages in the two following winters and three tropical cyclones that passed through the Gulf of Mexico in 1980. Twenty-four months after Frederic, the hurricane's geomorphic modification of the islands remained evident. In September 1981, the Chandeleur barriers were still segmented by 14 hurricane channels and the mean beach width was 60 m. whereas prior to Hurricane Frederic the barrier beach was continuous throughout the study area and the mean beach widths was 170 m. The slow partial recovery of the barriers lends support to the hyposthesis that the Chandeleur Islands are being transformed from a continuous chain of barrier islands into a series of small islets and shoals. The transformation is a consequence of the tfrequent passage of tropical cyclones thorugh the northern Gulf of Mexico, the lack of a sediment supply to the Chandeleur barrier system, and the subsidence of the St. Bernard Delta surface underlying the islands.