Facts and Figures: A major extra-tropical cyclone Xynthia caused one of the biggest compound events of its kind in Europe on 28 February-1 March 2010. It comprised: (a) a coastal flood, triggered by a storm surge with a 100-year return period in many locations combined with a high tide, that impacted the western coast of France, and (b) a windstorm with measured wind gusts up to 238 km/h affected the northern coast of France. There were 41 fatalities attributed to flooding and 6 to wind-related incidents. Insured losses of 1.5 billion € were split almost exactly 50% each between flood and wind.

The COMPASS approach: We will use ERA5-based hydrodynamic reconstructions of (Delft3D), local exposure data and multivariate, microscale vulnerability models, pan-European exposure data and wind damage functions, with validation based on detailed insurance loss data on both damage components. Attribution will be done using counterfactual wind and sea level, as well as counterfactual exposure and vulnerability drivers using HANZE exposure and ongoing vulnerability research of the COMPASS partners.