The Role of Storm‐Driven Seaward Sediment Flux in Coastal Barrier Dynamics Is an Enduring Puzzle

Abstract

AbstractCoastal barrier systems are low‐lying environments that bear the brunt of storm impacts, with cumulative and complex consequences for barrier evolution. Most studies of barrier responses to storms examine what happens when water and sediment get driven landward across a barrier from its ocean side. Sherwood et al. (2023, https://doi.org/10.1029/2022jf006934) investigate the effects of overland flow and sediment transport forced across a barrier in the opposite direction—from its sheltered side, seaward. Using high‐resolution imagery of a barrier island observed before and after a hurricane, Sherwood et al. (2023, https://doi.org/10.1029/2022jf006934) show that “outwash” flow across the barrier shifted several times more sediment by volume than is typically reported for beach and dune erosion from onshore forcing. Their findings are remarkable because they are not exceptional: a related survey of barriers along the Atlantic and Gulf Coasts of the USA observed patterns of outwash morphology essentially everywhere. Insights into outwash morphology open exciting questions regarding the overlooked role of storm‐driven seaward sediment transport in barrier dynamics, with important implications for post‐storm barrier recovery and barrier evolution over decades to centuries.