First World Congress of International Consortium on Geo-disaster Reduction (1st ICGdR World Congress)

Glacial debris flows are active cryospheric hazards in glacierized mountain regions under climate change, but their evolution and extreme climatic triggering patterns remain poorly constrained. This study investigates the response of glacial debris-flow activity to climate change in the Parlung Tsangpo Basin, southeastern Tibetan Plateau, by compiling a long-term activity inventory, analyzing its spatiotemporal patterns, and identifying the associated extreme climate conditions (Stoffel & Huggel, 2012).
A regional inventory for 1985–2024 was compiled using historical spaceborne photographs and Landsat imagery. Glacial debris-flow activity was identified from diagnostic geomorphic evidence, including proglacial source connectivity, refreshed channels, enlarged or reworked fan deposits, and newly exposed fan deposits.
The inventory reveals marked temporal variability and spatial clustering. Annual activity peaks generally occurred in years with anomalously wet conditions, while decadal activity increased strongly in the most recent decade. Spatially, debris flows were concentrated along major glacier-fed valleys and the main Parlung Tsangpo corridor, where steep terrain, abundant loose sediment, glacierized source areas, and efficient source-to-channel connectivity coincide (Yu et al., 2021).
The identified triggering patterns reveal a characteristic cold-season anomaly pattern, with anomalously high cold-season temperature and deficient snowfall. These warm and snow-poor conditions may weaken seasonal freezing, enhance early melt, reduce snow-cover protection, and expose moraine and channel sediments earlier in the year. Later rainfall or meltwater input may then trigger debris-flow initiation (Hirschberg et al., 2021). These findings suggest that glacial debris-flow activity reflects seasonal preconditioning followed by hydrological activation, highlighting the importance of cold-season climate anomalies in hazard assessment under climate change.

Glacial debris flows; Remote sensing; Landsat; Spatiotemporal correlation; Extreme climatic triggers; Southeastern Tibetan Plateau