A Climatology of Tropical Storm and Hurricane Strikes to Enhance Vulnerability Prediction for the Southeast U.S. Coast

A simple model of the average swath of tropical storm and hurricane-force winds to the right and left of storm centers is developed and utilized to evaluate the geographical and temporal distribution of storm strikes at "point locations" along the subtropical coast of the United States. The specific area of study is from South Padre Island, Texas, to Cape Hatteras, North Carolina. The time of record is 100 years from 1901 through 2000. The analysis illustrates the great geographical variability with high frequencies of tropical storm and hurricane strikes in southeastern Louisiana, southern Florida, and eastern North Carolina. Coastlines with lower frequency strikes are located along the western coastline of the Gulf of Mexico in southern Texas, the northeastern coastline of the Gulf in Florida from near Apalachicola southward to St. Petersburg, and especially along the South Atlantic coast from Daytona Beach, Florida, northward to the vicinity of Charleston, South Carolina. Temporal variability is great and significant, however, and with the exception of the northern Gulf Coast, most coastal sites have experienced pronounced clusters of strikes separated by tens of years with very few strikes. The occurrences of tropical storm and hurricane events over the Gulf of Mexico are related to La Nina, neutral, and EI Nino seasons, but the clusters of strike events and longer runs of seasons with minimal activity cannot be explained on the basis of ENSO indices alone. Our findings have important implications for storm clusters and vulnerability prediction along coasts.