ABSTRACT Ba, A. and Senechal, N. Extreme winter storm versus summer storm: morphological impact on a sandy beach This contribution presents the morphologic response of a double-barred sandy beach facing the Atlantic swells in the south west of France under two storm events: the first one occurring during summer period while the beach is experiencing seasonal accretive conditions and the second one during winter while the beach is experiencing seasonal erosion conditions. Shoreline positions, inner bar positions and beach states were extracted from rectified merged video data. Despite a significant difference in usually considered storms thresholds (Hs, duration), the winter storm (Joaquim) being associated to Hs up to 8.5 m during 120 hours and the summer storm being associated to Hs up to 4.5 m during 17 hours, the shoreline and the inner bar positions one week after the apex of each storm were very similar to the one observed previous the apex. Analysis of wave conditions preceding the two events indica...