Preprints
https://doi.org/10.5194/egusphere-2026-6868
https://doi.org/10.5194/egusphere-2026-6868
12 Nov 2026
 | 12 Nov 2026

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

Ankit Pramanik, Mathieu Morlighem, and Mohd. Farooq Azam

Abstract. 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.

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Ankit Pramanik, Mathieu Morlighem, and Mohd. Farooq Azam

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Ankit Pramanik, Mathieu Morlighem, and Mohd. Farooq Azam
Ankit Pramanik, Mathieu Morlighem, and Mohd. Farooq Azam
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Short summary
On 26 August 2026, bedrock and part of a glacier near Langtang Lirung, Nepal, broke away, causing a destructive flood. The rest of the glacier now ends at a steep cliff. Using a computer model, we tested two futures: the glacier sheds ice in small pieces that pose little risk, or it flows over the cliff edge and later falls in larger chunks. In both, its speed doubles right after the collapse. If it hangs over the edge, it stays under enough strain to crack, making another collapse possible.
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