  The decisions of whether and how to evacuate during a climate disaster are
influenced by a wide range of factors, including sociodemographics, emergency
messaging, and social influence. Further complexity is introduced when multiple
hazards occur simultaneously, such as a flood evacuation taking place amid a
viral pandemic that requires physical distancing. Such multi-hazard events can
necessitate a nuanced navigation of competing decision-making strategies
wherein a desire to follow peers is weighed against contagion risks. To better
understand these nuances, we distributed an online survey during a pandemic
surge in July 2020 to 600 individuals in three midwestern and three southern
states in the United States with high risk of flooding. In this paper, we
estimate a random parameter logit model in both preference space and
willingness-to-pay space. Our results show that the directionality and
magnitude of the influence of peers' choices of whether and how to evacuate
vary widely across respondents. Overall, the decision of whether to evacuate is
positively impacted by peer behavior, while the decision of how to evacuate is
negatively impacted by peers. Furthermore, an increase in flood threat level
lessens the magnitude of these impacts. These findings have important
implications for the design of tailored emergency messaging strategies.
Specifically, emphasizing or deemphasizing the severity of each threat in a
multi-hazard scenario may assist in: (1) encouraging a reprioritization of
competing risk perceptions and (2) magnifying or neutralizing the impacts of
social influence, thereby (3) nudging evacuation decision-making toward a
desired outcome.
