On August 26 a glacier collapsed in the Langtang region of Nepal near the China border, triggering an ice and rock avalanche. This apparently entered the Lhende Khola, a tributary of the Bhote Koshi river, where it either caused or contributed to a temporary blockage. When this burst, a catastrophic flash flood travelled almost 100 kilometres downstream.A glacier collapsesThere’s nothing to stop the avalanche down the Trishuli river valleyDid warm conditions play a role?There is increasing interest in the role of unusually warm conditions and glacial permafrost instability. Warming can increase meltwater penetration into the crevasses of glaciers and weaken ice-rock bonds. British Antarctic Survey researchers reported unusually high ground temperatures two days before the collapse.Satellite images stitched from Copernicus Sentinel-2 dataVideo sources: Gyirong Port – AP News_; Boulder – ABC News; Fast moving water – @pujanpokhareofficial/InstagramLevan Tielidze has received funding from the Australian Research Council.Digital Storytelling Team does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.