Regional Assessment Using Public Webcams of the Role of Post-Storm Recovery in the Seasonal Variability of Beach Width

Understanding the mechanisms and times required for beaches to recover after extreme storms, as well as the effect of these episodic setbacks on long-term coastal erosion trends, is crucial for anticipating changes and implementing effective management strategies. A storm can have significant impacts on the coastline, resulting in retreats of several meters within hours. The natural recovery of the beach in the hours/days following a storm varies greatly between sites, ranging from a few days to several months. In this study, we examine the regional variability in coastal response during winter storms and post-storm recovery, using a beach width indicator obtained through the analysis of public webcam images on event, seasonal, and multi-year time scales. Video-derived shoreline positions were used to calculate weekly average beach widths at 11 sites along the coastline of Occitanie. The analysis demonstrated that storm responses and seasonal trends exhibit significant variability despite similarities in morphologies, and exposure to storm waves. Although post-storm recovery following the major events of 2021 and 2022 was nearly complete and very rapid for most sites, some beaches experienced prolonged recovery periods, requiring several months to return to their initial position. While the results indicated that storm events were sufficiently spaced to allow these beaches to recover, a series of events in autumn 2023 raises questions about this recovery capacity and underscores the potential impact of singular events on medium-and long-term coastal evolution trends