This study aims to better understand coastal processes associated with extreme cyclonic events through the study of the coastal changes, flooding and damage that resulted from the passage of a category 5 hurricane (Irma) on 6 September 2017 over the islands of Saint-Martin and Saint-Barthélemy in the Lesser Antilles. The analysis shows the effects of coastal structures and streets on flow channelling, on the amplification of some erosion types, and on water level increase. Positive spatial correlation is found between damage intensity and marine flood depth.
Hurricane Irma was exceptional, but, the authors argue, the disaster is also inevitably due to political, social and economic factors. For three decades, the demographic and urban development along the coasts of the islands of Saint-Martin and Saint-Barthélemy contributed to the creation of a catastrophe. Laws and urban planning regulations exist but are seldom or not enforced at all, just like coastal regulations, which are inconsistent. The paper concludes that the goal now is to use this extreme experience in order to optimize future territorial planning on small islands.