Accumulative marine coastal forms of the Azov-Black Sea basin are a key element of coastal abrasion-accumulative geosystems and a valuable commercial resource. Monitoring of the accumulative forms dynamics in the region is a necessary component for successful management of the coastal zone and timely adoption of measures for coastal protection. The purpose of the work is to determine the qualitative and quantitative characteristics of the transformation of the Lake Bogaily Barrier Beach influenced by storms, in particular the extreme storm of November 26-27, 2023. The work uses materials from long-term monitoring observations, satellite images, simulation results of hydrological and lithodynamic processes, literary and archival sources. It was established that in the last 60 years the configuration and topography of the studied accumulative form have changed significantly. Periods were noted when the morphological and dynamic features of the accumulative form did not undergo fundamental changes as well as periods of their significant transformation. In particular, during the storm on November 26-27, 2023, the configuration and topography of the Lake Bogaily Barrier Beach was completely redesigned. The paper reveals characteristic features of the accumulative form dynamics during the storm. The accumulative body was displaced into the water area of the lake. The magnitude of this displacement significantly exceeded that of the retreat of the adjacent bedrock shores. The longitudinal and transverse structure within the barrier beach that existed for several decades has been completely transformed. It is concluded that any extreme storms play a decisive role in the variability of coastal accumulative forms in the region.