Combining Probabilistic Hazard Information Forecast Graphics with Wireless Emergency Alert Messages: An Exploratory, Qualitative Study

Abstract Since 2019, National Weather Service (NWS) offices have been able to issue 360-character Wireless Emergency Alert (“WEA360”) messages for tornadoes. NWS is now considering changing from a “deterministic” to a “probabilistic” warning paradigm. That change could possibly influence how WEA360 messages for tornado are issued in the future. Recent experimental studies have found that probabilistic hazard information (PHI) forecast graphics improve consumers’ risk perception for tornadoes, but findings from these studies concerning whether PHI forecast graphics improve people’s protective action decision-making are mixed. The present study therefore investigated how mock PHI-enhanced WEA360 messages might influence people’s risk perception and protective action decision-making. Analysis of qualitative data gathered from a combination of questionnaire and focus group interview methods conducted in collaboration with 31 community members in Denver, Colorado, indicated that inclusion of PHI forecast graphics within WEA360 messages elicited high levels of understanding and message believability but did not consistently lead to appropriate precautionary intent. Because warning response is a complex social phenomenon, PHI may not significantly improve protective action decision-making if PHI forecast graphics are eventually presented to consumers via the Wireless Emergency Alerts system. Factors that PHI stakeholders should consider before the adoption of PHI-enhanced WEA360 messages for consumers are discussed. Significance Statement This study examines how consumers respond to and talk about mock WEA360 messages for tornadoes that contain embedded PHI forecast graphics. As NWS considers moving to a probabilistic warning paradigm, stakeholders will need to determine how PHI forecast graphics might be communicated directly to consumers, if at all. Our findings suggest that combining WEA360 messages with PHI forecast graphics creates challenges and complexities related to consumers’ assessment of personal risk and protective action decision-making. Overall, the study suggests that any future PHI-enhanced WEA360 messages provided directly to consumers, if at all, must avoid discrepancies (even subtle) between the level of risk represented by the PHI forecast graphic and the protective action guidance included in the text of the messages.