Coastal Inundation from Non-Landfalling Tropical Cyclones along the Central Coast of Vietnam

Tropical cyclones, even without making direct landfall, can generate severe coastal inundation through multiple mechanisms. These events are increasingly recognized as critical hazards for Vietnam’s central coast, where narrow continental shelves and complex coastal topography amplify hydrodynamic responses. This study examines several historical tropical cyclones, including Typhoon Rai (2021), which caused significant flooding in parts of Vietnam’s central coast. Using meteorological reanalysis and tide-gauge records, we quantified water-level anomalies and identified the dominant forcing mechanisms. Results indicate that inundation during these events was not primarily controlled by pressure-driven storm surge but rather by the combined effects of low-frequency waves, wind setup, and local bathymetric amplification. The findings highlight that non-landfalling storms represent a significant yet underappreciated coastal flood hazard for Vietnam. Conventional early warning systems, which often focus on landfalling tracks, may underestimate inundation risk when storms remain offshore but retain strong intensity. Incorporating offshore storm scenarios, wave–surge coupling, and site-specific geomorphological factors into forecasting frameworks will improve predictive skill and strengthen coastal resilience. This research enhances understanding of the impacts of non-landfalling tropical cyclones in the context of coastal engineering and disaster preparedness, providing a scientific foundation for improved early warning strategies and adaptive coastal management in Vietnam and other cyclone-prone regions with similar geomorphic settings.