Forecasters' mental models of flash flood forecasts and warnings

How do National Weather Service (NWS) forecasters conceptualize flash floods (including exposure, effects, mitigation), use information in creating warnings, and then communicate flash flood warnings? How do these forecasts perceive how flash flood forecast and warning information (including uncertainty) is interpreted and used by public officials, media personnel and the general public?

To begin to address these questions we conducted in-depth face-to-face interviews with forecasters (“experts”) to characterize their mental models of the flash flood forecast and warning process and engage them in participative decision modeling (influence diagram construction). A mental model is an explanation of an individual's thought process for how something (e.g. flash flooding) functions in the real world. This can include perceptions of the various parts of a system, the relationships between these parts, and the person's perception about their own or other's exposure, effects, mitigation, and experience with respect to the system. Forecasters' mental models of flash floods and flash flood forecasting can thus shape their behavior with respect to warning decisions and as well as communication with respect to the system. Data was obtained through one-on-one decision elicitation interviews with NWS forecasters in Boulder, Colorado, followed by a mediated group decision-modeling session. Individual interviews opened with an elicitation of each expert's mental model of the hazard and the warning system, and then focused on development of an influence diagram, representing the forecasters' beliefs about how forecast and warning decisions are made in the face of uncertainty. Interviews used the “assembly method” – listing all relevant factors followed by identifying how each factor is related to one another to create a general diagram showing how warning information is constructed and communicated. Diagrams identify underlying meteorological conditions and how those trigger and influence communication design, information dissemination, and decision responses, from the point of generation by forecasters to the point of consumption by public officials, the media, and members of the public. The mediated group session is the basis of a comprehensive “expert” influence diagram of the flash flood forecasting and warning system that will be the primary focus of this presentation. We also discuss how results from the forecaster mental modeling are being used to guide mental model interviews with public officials (e.g., emergency managers), media, and the public.