Perceptions and Expected Immediate Reactions to Severe Storm Displays

Abstract

The National Weather Service has adopted warning polygons that more specifically indicate the risk area than its previous county-wide warnings. However, these polygons are not defined in terms of numerical strike probabilities (p ). To better understand people's interpretations of warning polygons, 167 participants were shown 23 hypothetical scenarios in one of three information conditions-polygon-only (Condition A), polygon + tornadic storm cell (Condition B), and polygon + tornadic storm cell + flanking nontornadic storm cells (Condition C). Participants judged each polygon's p and reported the likelihood of taking nine different response actions. The polygon-only condition replicated the results of previous studies; p was highest at the polygon's centroid and declined in all directions from there. The two conditions displaying storm cells differed from the polygon-only condition only in having p just as high at the polygon's edge nearest the storm cell as at its centroid. Overall, p values were positively correlated with expectations of continuing normal activities, seeking information from social sources, seeking shelter, and evacuating by car. These results indicate that participants make more appropriate p judgments when polygons are presented in their natural context of radar displays than when they are presented in isolation. However, the fact that p judgments had moderately positive correlations with both sheltering (a generally appropriate response) and evacuation (a generally inappropriate response) suggests that experiment participants experience the same ambivalence about these two protective actions as people threatened by actual tornadoes.

Preparing for Doris: Exploring Public Responses to Impact-Based Weather Warnings in the United Kingdom

“…This is consistent with our finding that some participants in border areas perceived their local warning level to be yellow, while others perceive it to be amber. It may also reflect a broader tendency for those on the periphery of warning areas to perceive their own level of risk to be lower than those in the center (Jon et al 2018;Lindell et al 2016). Once again, this highlights the importance of members of the public being able to identify the warning level in place for their location.…”

“…Second, when a location is close to the border of two warning levels on the map how is local risk level interpreted? Research on tornado warning maps suggests that people perceive areas near the warning periphery as lower risk than central areas, despite this not being the case (Jon et al 2018(Jon et al , 2019Lindell et al 2016). For U.K. weather warnings, it is thus useful to determine whether those close to the border of different warning levels (e.g., yellow and amber) perceive personal risk differently than those clearly within one warning level and whether this affects behavioral response.…”

Advances in Spatial Risk Analysis

“…How can this be done most effectively, if there is to be a balanced response without risking panic? Jon, Huang, and Lindell (2019) in this special issue consider the case of tornados in the United States. They note that little research has been conducted into how people actually interpret and respond to the warning polygons used by the National Weather Service.…”

Geophysical and Social Influences on Evacuation Decision-Making: The Case of Hurricane Irma

“…The method in which hazard information is conveyed through warnings and graphics can also affect how individuals perceive data to inform their decision to evacuate. It has been observed that the type of graphic presented to an individual can influence their protective action decisions and that different methods of information portrayal with natural hazards can alter an individual's risk perception [41][42][43][44]. For example, the study by Ash tested the response to three different tornado warning designs [41].…”