Intra‐Seasonal Variability of Serial Clustering of Severe European Winter Windstorms

Abstract Clustering of severe European winter windstorms causes large economic loss and social‐environmental impacts. We present a detailed analysis of the intra‐seasonal variability of clustering of severe European winter windstorms based on ERA5 reanalysis, with the focus on impact‐relevant footprints of storm systems for the extended winter season (ONDJFM). The magnitude of clustering is quantified using the dispersion statistic on fixed 91‐ and 30‐day timescales, as well as shorter 21‐, 15‐, and 11‐day time‐development windows. Results indicate an increase in the magnitude of clustering in the later part of ONDJFM. Our analysis identifies for the first time that end‐user (including the insurance sector) relevant storm clustering exhibits two intra‐seasonal periods of enhanced clustering, especially in the densely populated regions of western central Europe (e.g., UK, Benelux, Northern France, Germany). Links to important large‐scale modes (North Atlantic Oscillation ‐NAO, Scandinavian Pattern ‐SCA and East‐Atlantic Pattern ‐EA) are analyzed as potential drivers.