The use of a micro-scale index to identify potential death risk areas due to sea-flood surges: lessons from Storm Xynthia on the French Atlantic coast

International audienceStorm Xynthia (February 2010) was responsible for a large sea surge along theFrench Atlantic coast. It resulted in the flooding of low-lying coastal areas during the night.Urbanized areas were impacted and 41 people died by drowning in their homes. Thelocation and type of construction of the houses in the affected area contributed to the deathtoll. The fact that the inadequacy of construction with regard to coastal flood hazard couldlead to death was one of the most important lessons of the storm. The French governmentdecided to buy back and scrap the most dangerous buildings hit by Xynthia. In order toprevent future deaths by drowning, we have developed a tool (the V.I.E. index) to identifyhouses where a risk of death due to a coastal flood cannot be excluded. The goal is topropose individual-based solutions for risk mitigation of residential houses. This tool usesa micro-scale-level analysis along with four criteria: (1) the potential water depth perhouse, (2) the distance between the dike and the house, (3) the architectural typology and(4) the closeness to rescue point. The methodological background and the first results forthree towns are presented in this paper. Limitations and further developments are alsodiscussed