Emotional responses and perceptions of false alarms in flood warnings and their impact on evacuation action: an empirical analysis of the Kyushu Region, Japan

Repeated false alarms for adverse weather events may reduce people’s willingness to take appropriate actions, such as evacuation. Therefore, understanding how false alarms influence perceptions and actions is essential for building effective early warning systems (EWS). We aimed to examine perceptions, emotions, and actions regarding false flood warnings in Japan. Specifically, we investigated (1) people’s definition of hits; (2) emotional responses toward false alarms; (3) the effect of the false alarm ratio (FAR) on the perceived FAR (pFAR) and the heterogeneity of this effect according to participants’ definition of hits; and (4) the effect of pFAR on evacuation action and the heterogeneity of this effect according to the emotional responses toward false alarms. We used newly constructed municipality-level FAR data and questionnaire data collected from residents of the Kyushu Region (n = 997). The results showed that participants tended to consider a warning as a hit when the river water reached a hazardous water level or when an overflow or levee breach occurred. Furthermore, false alarms were associated with decreased negative emotions (i.e., sadness and anger) and increased positive emotions (i.e., being pleased and at ease). We found a non-significant relationship between FAR and pFAR, which was maintained regardless of the participants’ hit definitions. However, pFAR had a significantly negative effect on the probability of evacuation, and this negative effect was weaker among those who experienced positive emotions toward false alarms. These findings suggest that effective EWS require risk communication strategies that consider emotional responses to false alarms.