Climate warming preconditions Himalayan slopes for post-earthquake cascading hazards

The Sedongpu Gully in the Eastern Himalaya has experienced a sharp increase in rock–ice avalanches in recent years. Here we examine how climatic and seismic forcings jointly precondition slope disruption and trigger multi-stage hazard cascades by integrating multi-source remote sensing observations and numerical simulations. We identify at least 24 hazard-cascade events in the Sedongpu gully between November 1961 and October 2023, with a cumulative slope-material loss exceeding 700 ± 22 million m³ that repeatedly dammed the Yarlung Zangbo River. Our findings suggest that sustained glacier and snow retreat and climatic warming act as long-term destabilizing processes that progressively modify slope boundary conditions, while strong seismic shaking provides an additional disturbance to these preconditioned slopes. Furthermore, deformation analysis and numerical simulation suggest that future potential rock–ice avalanches could still generate large volumes of debris to block the river. This research establishes an integrated framework for investigating and assessing multi-stage cascading hazards in tectonically active and climate-warming mountain regions. Remote sensing data and numerical simulations suggest earthquake-induced rock-ice avalanches in the Sedongpu gully lead to cascading hazards in areas that have been destabilized by the long-term action of climatic warming and retreating glaciers