Estimating the Vulnerability of U.S. Coastal Areas to Hurricane Damage

Although hurricanes can strike most U.S. coastal states and cause damage in noncoastal states as well, some coastal areas are much more likely than others to experience the most costly storms. In the U. S., 40 percent of all major hurricanes have battered Florida, and 83 percent of category 4 or 5 hurricane strikes have pummeled either Florida or Texas (Blake et al., 2007). It is not surprising, therefore, that the Texas and Florida coastlines have experienced much more damage from hurricanes than other southeastern coastal areas. Of the 10 most costly hurricanes, 9 have struck the Texas or Florida coasts (Table 1). Hurricanes have become much more costly in recent years; 8 of the 10 most damaging hurricanes have occurred since 2004. In total, the seven hurricanes in 2004 and 2005 caused $79.3 billion in insured losses. An increase in hurricane activity may explain some of the increased cost. After a period of infrequent hurricane activity between 1971 and 1994, hurricane activity has increased in recent years. The five most intense consecutive storm seasons on record occurred between 1995 and 2000. In 2004 an unprecedented four hurricanes, viz. Charley, Frances, Ivan and Jeanne, damaged Florida communities. And the 2005 hurricane season was the busiest and most costly in United States history, with 28 named storms, 15 of which were hurricanes, including Katrina (South Carolina Department of Insurance, 2007, 14). Although a period of increased hurricane activity may have contributed to increased hurricane damage, other factors such as population growth and increased property values have contributed to the higher costs. In order to examine factors that influence hurricane damage we consider eight southeastern states: Alabama, Florida, Georgia, Louisiana, Mississippi, North Carolina, South Carolina, and Texas. We focus on this area because the greatest likelihood of severe damage from hurricanes is along the coastlines of the southeastern Atlantic and Gulf of Mexico states where 112 major hurricanes have struck between 1851 and 2006 (Blake et al., 2007). Understanding more about factors that increase coastal area vulnerability will help mitigate other coastal threats such as northeasters. Northeasters, which are powerful storms that have winds that blow from the northeast, can generate storm surge and waves that cause even greater damage than hurricanes. The Ash Wednesday storm of 1962, which was one of the most damaging northeasters, created waves more than 30 feet high and caused millions of dollars in damage along the mid-Atlantic coast. In this study, we consider the various factors that increase an area’s vulnerability to hurricane damage. We focus on the risk to the built environment not the loss of life from hurricanes, which has been greatly reduced in recent years, generally. However, the