The Nepal Flood: What We Know

On 26 August 2026, a mass of rock and ice broke off the north face of Langtang Lirung, on the Nepal/Tibet border, and sent a debris flow down the Bhote Koshi and Trishuli rivers through Rasuwa and Nuwakot districts.

I'm a hydropower engineer. This is an account of what's established about how the flood happened, what's still unresolved, and what freely available satellite data shows about the ground it moved through, recorded on 27 August, one day after the event. Everything here is provisional and will be revised as ground access becomes available.