Glacial Debris Flow Blockage Event (2018) in the Sedongpu Basin of the Yarlung Zangbo River, China: Occurrence Factors and its Implications

Abstract The cryospheric disasters, especially glacier disasters and permafrost disasters, has arose great risks to people’s lives in Tibetan Plateau under climate warming. In this paper, the glacial debris flow blockage event on October 17th, 2018, in the Sedongpu basin of the Yarlung Zangbo River is taken as an example to analyse the occurrence and development of glacier disasters in the region. It is found that the topography and climate background determine the hazard happens periodically, and they are fundamental for the weak vulnerability here. It can be reflected by the glacier dynamic simulation with Elmer/Ice model, which showed that the ice flow was extremely fast. Both heavy rain and an earthquake were triggering factors of the ice avalanche that led to the glacial debris flow. Combining analysis with documented records, we also proposed an assessment procedure for disaster-prone glaciers in this region, with key identification indices such as the type of glacier, presence of debris, slope of glacier, etc. The results indicated that the glacier disasters may seriously affected the Sichuan-Tibet Highway and local people. This synthesis study has extensive applicability and practical significance in glacier disaster prevention and mitigation under a changing climate.