Developing an effective evacuation strategy for hurricane zones presents challenges to emergency planners because of spatial differences in geophysical risk and social vulnerability. This study examines spatial variability in evacuation assistance needs as related to the hurricane hazard. Two quantitative indicators are developed: a geophysical risk index, based on National Hurricane Center and National Flood Insurance Program data, and a social vulnerability index, based on census information. These indices are combined to determine spatial patterns of evacuation assistance needs in Hillsborough County, Florida. Four evacuation dimensions are analyzed: population traits and building structures, differential access to resources, special evacuation needs, and a combination of variables. Results indicate that geophysical risk and social vulnerability can produce different spatial patterns that complicate emergency management. Different measures of social vulnerability also confound evacuation strategies and...

The use of levees for flood control has a long history in the United States in part because their relatively low construction costs and general effectiveness in protecting low-lying areas are politically expedient. Consequently, there are thousands of counties and communities relying on levees as their primary flood protection measure. However, levees can also promote floodplain development, placing more property at risk, and they have negative hydrological and environmental consequences. In addition, failures occur when design standards are exceeded or because of poor maintenance, leading to catastrophic losses. Recognizing these limitations, the Association of State Floodplain Managers has issued 25 recommendations regarding the use of levees, three of which are evaluated here in the context of Yuba County, California, a county that has experienced three major flood events in the last 25 years due to levee breaks. Faced with ongoing development pressures and suburban sprawl from Sacramento, Yuba County ...