How Close is Close Enough? A Discussion of the Distances Relevant to Personalizing Tornado Risk

Abstract

Risk perception and the desire to personalize and confirm warning information have been associated with protective action. Risk perception typically increases with close proximity to a threat, but research involving time, space and tornado risk perception has stopped short of attempting to define a distance at which an individual would believe they are personally at risk from a tornado. In this study, we surveyed 1023 individuals across the Southeastern United States at risk from tornadoes. The goal was to add to our understanding of the role of distance in tornado risk perception by quantifying an individual’s “worry distance.” The study examined an individual’s worry distance in multiple ways including three map-based warning scenarios. Our results indicated that participants would worry about their house or loved ones or take shelter in a tornado if it was on average within 11-12 miles. These distances were greater than the 7-8 miles at which they believed they could see, hear or feel the effects of a tornado. There was a considerable amount of variation in the self-reported distances, some of which can be explained by past exposure. When provided tornado warning maps with varying scales or county borders, neither map scale nor the presence of a border had an influence. The lack of any influence of map scale raises the question of how individuals consider objective geospatial distance when using a map-based warning for familiar or novel locations.