Seasonal variability in wave conditions drive corresponding cycles of erosion and accretion along sandy beaches. Despite the fact that these oscillations are well documented at numerous sites throughout the world, the physical processes driving beach recovery remain poorly understood. Using field data from a low sloping, dissipative beach in the U.S. Pacific Northwest we show that the onshore migration of intertidal sandbars contributes to beach growth in a rapidly prograding system. Over a six week period two intertidal sandbars are shown to migrate onshore resulting in the generation of a low relief berm and local beach width increases of up to 20 m. Although significant alongshore variability of intertidal morphological change was observed, a 2.5 km stretch of coast is shown to experience beach growth as a result of intertidal bar welding.@en