Hurricanes, Risk and Hazard

Geography of Risk

An average of two hurricanes reaches the coast of the United States each year. In the United States, hurricanes most frequently make landfall along the shores of Eastern Florida, Georgia, South Carolina, and North Carolina; however, coastlines along the Gulf of Mexico as well as the Atlantic coast from Virginia to Maine are also at risk. Hurricanes often span hundreds of miles in width and thus are capable of causing widespread damage to inland areas. Most of the substantial damage and loss of life attributed to hurricane hazards transpires within 60 to 100 mi. (miles) of where the storm makes landfall.

Population growth along the coastal areas has increased the number of Americans at risk from hurricane hazards. The U.S. Census Bureau estimated that in 2007, more than 35 million Americans along the coastline from North Carolina to Texas were at high risk from hurricane-related threats. In addition, the locations most vulnerable to hurricane events experienced 247% population growth since the 1950s. Despite the increasing coastal population, hurricane-related deaths have dramatically decreased throughout the past century due in part to better warning systems. However, economic losses resulting from hurricane hazards have greatly increased because of rising property values, new construction, and increased industrialization in coastal areas.

Hurricane Hazards

Hazards attributed to hurricane events vary greatly in magnitude, geographic extent, and the resulting damage. The hazards that result in the most damage to coastal areas during a hurricane include storm surge, high-speed winds, heavy rainfall, flooding, and tornadoes. These hazards are described in further detail below.

Historically, the storm surge has been responsible for the majority of hurricane-related deaths. The storm surge is a hurricane tide that is primarily driven by strong winds. Storm surges can raise local ocean water levels by more than 20 ft. (feet) and can extend along a coastline for more than 100 mi. Much of the damage caused by a storm surge is limited to locations near the coastline. Debris carried by these waves contributes to their destructive force, causing significant damage to buildings and property located in low-lying areas. The most devastating storm surge in U.S. history occurred during the Galveston Hurricane of 1900, where an estimated 8,000 to 12,000 people on Galveston Island, Texas, were killed when a 15- to 18-ft. storm surge inundated the island.

High-speed winds are another hazard related to hurricanes. Hurricane-force winds exceeding 74 mi./hr. (miles per hour) often suspend large debris into the air, causing widespread damage to homes, buildings, trees, and utility lines. Hurricane-force winds are responsible for some of the highest wind speeds ever recorded. Hurricane Celia generated sustained winds of 161 mi./ hr. as it made landfall on the coast of Corpus Christi, Texas, in 1970, and Hurricane Camille, in 1969, struck the Louisiana coastline with sustained winds reported at 172 mi./hr.

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