Overlooked but widespread severe coastal erosion prior to typhoon landfall

With increasing frequency and intensity under global climate change, storms, particularly typhoons, have become critical drivers reshaping coastal morphology. However, researches capturing the full morphodynamic sequence, especially the pre-landfall phase, remain scarce due to the challenges of field observations under extreme conditions. To address this, continuous observations were conducted throughout the Typhoon Fung-wong on the Yangtze Estuary intertidal flat. Here we found that, the loose and easily erodible surface layer of the intertidal mudflat was primarily eroded prior to typhoon landfall, exposing stiff, well-consolidated subsurface sediments. Subsequently, bed-level change remained minimal during peak hydrodynamics at typhoon landfall, showing that vertical sediment properties modulate morphodynamic responses. The decade-long continuous observations at the Sheshan Station in the Yangtze Estuary confirmed this severe pre-landfall erosion which also appears common across both China and the United States. This highlights the importance of pre-landfall erosion and sediment stratification in storm-driven coastal change prediction and management. Observations over a decade at the Sheshan Station in the Yangtze Estuary support pre-landfall erosion, highlighting the necessity to consider such erosion and sediment stratification in predictions of storm-induced coastal alterations, according to analysis of morphodynamic observations and sediment dynamics of Typhoon Fung-wong.