Brief communication: Impact of a bedrock–ice collapse on glacier dynamics: the 2026 Gyirong-Rasuwa disaster, Central Himalaya, Nepal

On 26 August 2026, a massive collapse of bedrock and glacier ice from the north face of Langtang-Lirung, Nepal, triggered a catastrophic flash flood, leaving a steep, high-relief ice cliff. Two post-disaster scenarios are plausible: (1) continual small-scale break-off; and (2) creep over the relief, forming a hanging glacier prone to episodic, larger collapses. We test both with an ice-flow model. In both scenarios, ice velocity doubles immediately after the collapse and then gradually recovers. Continual break-off limits tensile-stress rise while hanging-glacier sustains tensile stress within the reported range of ice tensile strength, promoting crevassing and fracture, if not collapse.