Coastal lake sediments contain a stratigraphically and chronologically distinct record of major hurricane strikes during late Holocene time. Frederic—a category 3 hurricane that struck the Alabama coast on the Gulf of Mexico in 1979—left a distinct sand layer in the nearshore sediments of Lake Shelby as a result of storm-tide overwash of beaches and dunes. Sediment cores taken from the center of Lake Shelby contain multiple sand layers, suggesting that major hurricanes of category 4 or 5 intensity directly struck the Alabama coast at ca. 3.2-3.0, 2.6, 2.2, 1.4, and 0.8 ka (14C yr), with an average recurrence interval of ∼600 yr. The Alabama coast is likely to be struck by a category 4 or 5 hurricane within the next century.
- Geological Society of America