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
Résumé
Storm Xynthia (February 2010) was responsible for a large sea surge along the
French 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. The
location and type of construction of the houses in the affected area contributed to the death
toll. The fact that the inadequacy of construction with regard to coastal flood hazard could
lead to death was one of the most important lessons of the storm. The French government
decided to buy back and scrap the most dangerous buildings hit by Xynthia. In order to
prevent future deaths by drowning, we have developed a tool (the V.I.E. index) to identify
houses where a risk of death due to a coastal flood cannot be excluded. The goal is to
propose individual-based solutions for risk mitigation of residential houses. This tool uses
a micro-scale-level analysis along with four criteria: (1) the potential water depth per
house, (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 for
three towns are presented in this paper. Limitations and further developments are also
discussed.