An experimental test of risk perceptions under a new hurricane classification system.

During a hurricane, it is vital that individuals receive communications that are easy to process and provide sufficient information to allow informed hurricane preparedness decisions and prevent loss of life. We study how different hurricane warning scales, the traditional Saffir-Simpson Hurricane Wind Scale (SSHWS) versus the newly developed Tropical Cyclone Severity Scale (TCSS), impact intent to evacuate and understanding of hurricane severity. We use a between-subject design where participants are assigned to either the traditional SSHWS or the new TCSS scale. We collected data in a large-scale (~ 4000 participants) online experiment to examine potential differences in comprehension, risk perception, anticipated evacuation, and preparation decisions among residents in U.S. coastal states prone to hurricanes. We find that participants using the TCSS scale are better at identifying the main hazard of a hurricane. For evacuation, the TCSS leads to significantly higher evacuation intent as opposed to SSHWS in cases where the TCSS is at least two categories higher (due to rainfall or storm surge being the main hazard rather than wind). In addition, the TCSS also seems to have a positive effect on taking appropriate precautionary measures, though not always at our stated significance level. Overall, our results demonstrate that people make better informed and more appropriate decisions with the TCSS as opposed to the currently used SSHWS. Protocol Registration The stage 1 protocol for this Registered Report was accepted in principle on 14 October 2024. The protocol, as accepted by the journal, can be found at: https://doi.org/10.17605/OSF.IO/AYXTK . The approved Stage 1 protocol is available here: https://osf.io/m3swr .