Risk based decision making for evacuation in an uncertain world

Evacuation is a possible response to the threat of flooding. However, evacuation can be costly with respect to time, money, and credibility. The decision-making process for mass evacuation is characterised by short reaction times and requires consideration of the probability of a certain impact, possible life-and-death situations and the economic impact. Evacuation can also reduce loss of life. However the frequency of evacuation-events is higher than flood-events because decisions are made on forecasts based on critical water levels which are less than the expected level of failure. A better understanding of heuristics and biases can improve judgments and decisions in cases of uncertainty. Authorities have to make a trade-off between the costs and possible benefits of evacuation when the disaster occurs. Decision makers (in multiple teams) and crisis managers can simultaneously provide multiple frames of reference about a certain phenomenon. This paper describes a decision support method and case study for The Netherlands for the use of “evacuation diagrams” to support decision makers (and crisis managers) to call for evacuation and the role of uncertainties