Stakeholders' issues for action during the warning process and the interpretation of forecasts' uncertainties

International audienceThis article considers the socio-geographical ap- proach carried out as part of the MedUp program. It presents a study of the ways that the French "actors" manage forecast uncertainties during a flash flood warning process. In order to better understand the role of forecasts' uncertainties in de- cision making, we focused on the actions people took and how what they say explains their actions. The practices of ac- tors involved in warnings for the Vidourle watershed (Gard, France), in particular, are analyzed using a practice-based approach. A set of categories of the "actors" was devel- oped based on their descriptions of the problems they faced during the flash flood warning, independent of their socio- professional status and position in the warning chain. Five actor profiles result from this: Translators, Managers, Com- mitted, Navigators and Vulnerable. For each profile, specific action contexts are defined, determining how each deals with uncertainty