Hurricane vulnerability and changes in vulnerability for coastal counties in the United States from 1961 to 1991

Coastal economic vulnerability to tropical cyclones has become increasingly evident over the past decade. Hurricanes Hugo, Andrew, Opal, and Fran rank among the ten costliest hurricanes in U.S. history and all have occurred over the past ten years. Increases in economic development of hurricane prone regions have resulted in increases in the frequency and in the intensity of hurricane disasters. These disasters represent the beginning of an alarming trend in hurricane losses.

This study examines the vulnerability of the United States coastline to potential economic disaster as the result of hurricanes. Vulnerability is defined as a combination of exposure and incidence. Exposure refers to wealth at risk to loss from hurricane winds and surge and incidence refers to the climatological probability of a hurricane landfall. We analyze one-hundred and seventy-four coastal counties for distributions of exposure and incidence. Understanding these distributions allows one to make an assessment of vulnerability, and over time, changes in vulnerability.

A direct relationship exists between changes in vulnerability and changes in potential hurricane damages. A relation is derived from hurricane normalization techniques presented in Pielke and Landsea (1998). This relationship between vulnerability and potential damage highlights the importance of examining vulnerability.

Within the study, coastal counties are ranked according to their relative vulnerability and change in vulnerability. Not surprisingly, Florida, North Carolina, and Texas are, in general, highly vulnerable to economic disaster as the result of a hurricane. These same states have also shown the greatest relative increases in vulnerability.

Analyses of vulnerability are useful to the emergency operations community. The results of this study should enable decision makers to better attack the problem of coastal vulnerability. During a time of limited state and federal government funds, these results should enable planners to allocate resources in a more proficient manner.