Exposure of US counties to Atlantic tropical storms and hurricanes, 1851–2003

Exposure of counties in the continental United States to tropical storm and hurricane conditions was determined using the historic record of storm tracks for the period 1851–2003. Two approaches were used to determine exposure: (1) cumulative number of hits, with a hit occurring when the storm’s path crosses a county and (2) cumulative exposure factor, which describes how much of the county has been exposed to tropical storm, hurricane, and intense hurricane-force winds. In both approaches the top 10 counties in terms of cumulative exposure are in coastal Florida, North Carolina, and Louisiana. An explanatory model was developed to describe the patterns in the documented exposure, which included distance to coast, latitude, longitude, size, and shape of the counties. Multivariate linear regression confirmed that much of the spatial variability in exposure to storm conditions can be explained with these simple parameters.