The Impact of Color-Coded Probabilistic Tornado Warnings on Risk Perceptions and Responses. Part II: Interviews

A tornado warning means that a tornado threat is imminent or occurring. Currently, tornado warnings issued by the U.S. National Weather Service (NWS) are binary--one is either in or out of the warning--and assume an even distribution of risk inside the warning. Because not every location in a warning shares an equivalent chance of being hit by a tornado, the NWS is considering issuing probabilistic tornado warnings in the future in order to convey more nuanced chances of exposure. The rapid-onset nature of tornadoes leaves little room for confusion about these risk messages. Yet, with few exceptions (Ash et al. 2014, Klockow 2013, Ling et al. 2015) there has been little research to investigate the public’s ability to accurately interpret and use probabilistic warnings. We are addressing these critical knowledge gaps through a mixed-methods research approach with an initial experimental design followed by interviews. Both methods evaluated different tornado warning visuals, including a deterministic warning (as is currently issued) and multiple probabilistic warning formats, as well as different locations in each visual.

This presentation will report results of the interviews. A structured, open-ended interview protocol was designed as a counterpart to the experiment. The interview included questions that mirror those from the experiment, which allows us to gain insight into the experimental results by revealing how and why people respond to the warning information in the ways that they do, including the reasons underlying the misunderstandings found in the experiment. The interview also included additional questions to reveal how people interpret and use warning information based on the real-world context of their lives and experiences. Interviews were conducted in-person in April 2019 with 36 members of the public who reside in or near Tuscaloosa, Alabama. This presentation will build on the experimental results reported in the first presentation (Part I) by discussing how and why interviewees discussed the perceived likelihood of a tornado hitting different locations, the perceived severity of damage if a tornado hits, and what behavioral responses they would engage in, each for the different warning visuals presented to them. For instance, the results suggest that people’s thinking about potential severity of tornado damage is complex and sophisticated, revealing systematic reasoning that is beyond a simple conflation with perceived likelihood. This presentation will also discuss people’s perceptions of time associated with the tornado threat and their worry about it. Finally, implications for future research will be discussed.