Appreciating geographic and temporal scales in flash flood research

International audienceFlash floods are characterized by their suddenness, fast and violent movement, rarity, small scale but high level of damage. They are particularly difficult to forecast accurately and leave very little lead-time for warnings. Flash floods can surprise people who are in the midst of their daily activities, with particularly serious impacts when people travel across roads vulnerable to flooding. Most of the people killed by flash floods in the US and France are in cars. What make motorists especially vulnerable? Experts call for a comprehensive integration of social and natural sciences and engineering to better understand public responses. My research addresses people's travel patterns during flash floods and uses a spatio-temporal analysis to better understand the link between human behaviors and sudden change of the environment. Using examples from France and from Texas, this presentation will show the main results of this interdisciplinary research using both qualitative and quantitative methods. It will demonstrate that « at risk » travel patterns result in a mix of three factors: spatio-temporal exposure, cognitive understanding of risks on the road, but also daily family and professional constraints