US Gulf Coast residents underestimate hurricane destructive potential

Ensuring human health and safety before, during, and after tropical cyclones is of major concern to scientists of many disciplines. As societies have continued to develop vulnerable coastal regions, tropical cyclone landfalls pose increasing challenges to survival and adjustment1,2. A persistent and life-threatening problem, in the face of increased societal vulnerability to tropical cyclone impacts, is that compliance with orders to evacuate ahead of an approaching storm remains below desired levels3. Although prior research has enumerated several factors that influence evacuation behavior ahead of tropical cyclones, none has considered the public's perception of the pattern in which cyclone destructive potential can increase with increasing cyclone intensity3-9. Yet, perception of tropical cyclone danger is an important predictor of evacuation behavior8. In this paper I show that most people do not realize that tropical cyclone destructiveness increases exponentially with increases in storm intensity. Three studies were conducted to examine peoples' perceptions of cyclone destructive potential and their likelihood of evacuation. In the first study, undergraduate students (n=349) provided damage ratings of hurricanes in each Saffir-Simpson category. A majority (75%) of students produced only linearly increasing damage profiles by cyclones. In the second study, a simple random sample (n=402) of US Gulf Coast residents who responded to a brief survey when a hurricane threatened revealed that a majority (63%) thought cyclone damages increased linearly with cyclone intensity and hence underestimated the damage major storms could produce. In the third study conducted before a hurricane landfall, a random sample (n=396) of Gulf Coast residents who received information about the exponentially-increasing damage potential of hurricanes reported significantly greater likelihood of evacuation than residents who received Saffir-Simpson information alone. Follow-up analyses revealed that although most of the participants in the third study reported an awareness of the Saffir-Simpson scale, a majority of them did not know about the levels of destructiveness associated with each category of cyclone. The author's results support the continued use of the Saffir-Simpson scale with an emphasis on educating the public about the exponential relationship between cyclone intensity and destructive potential. These studies are the first to illustrate the application of psychophysical law to perceptions of cyclone destructiveness and suggest that cyclone warnings might increase evacuation compliance by conveying the exponentially-increasing damage potential of approaching storms.

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