Why the Bhote Koshi Keeps Flooding: Glacial Lakes, Ice-Rock Avalanches and a Warming Himalaya (2026)

Climate & Environment No single cause is confirmed yet — scientists are weighing an earthquake-triggered landslide, an ice-rock avalanche and a draining glacial lake… By Laxman Rawal · Aug 26, 2026 Read the full story

Part of our continuing series — The Himalaya and Climate Change in 2026 . On the morning of 26 August 2026 , a wall of water surged out of Tibet and down the Bhote Koshi River into Nepal's Rasuwa district, tearing through the border settlements of Timure and… Travel Himalaya Nepal · News

What actually came down the valley

The maximum flooding was on the Lhende Khola , a tributary of the Bhote Koshi, with the trigger point roughly 25 km inside Tibet . From there the water funnelled through the Rasuwagadhi–Gyirong (Kerung) border zone and into Nepal. Whatever set it off happened… Travel Himalaya Nepal · News

A supraglacial lake — a pond on top of the ice

A supraglacial lake forms on the surface of a glacier, where meltwater collects in ponds that expand and merge into a larger body of water sitting directly on the ice. Because its bed and its banks are ice rather than rock, such a lake can fail suddenly: the… Travel Himalaya Nepal · News

An ice-rock avalanche — a natural dam that fails

In the second reading, favoured by ICIMOD's Saswata Sanyal and Sarthak Shrestha , a mass of rock and ice broke off a glacier and crashed into the valley floor. Debris on that scale can pile across a river and pond a lake behind it — a temporary, unstable… Travel Himalaya Nepal · News

An earthquake that shook the slope loose

The third explanation ties the flood to the ground itself moving. Foreign Minister Shishir Khanal has said an earthquake triggered the avalanche or landslide that blocked the Bhote Koshi. The USGS recorded an mb 4.4 earthquake in Tibet, and roughly seven… Travel Himalaya Nepal · News

A river that flooded twice in fourteen months

This is the part that should give pause to anyone who lives, trades or treks below these valleys. The Bhote Koshi and its Lhende tributary flooded once already, in July 2025 — a flood attributed at the time to drainage from a supraglacial lake in Tibet. That… Travel Himalaya Nepal · News

Langtang Valley Trek — 7 Days

Plan your trek NMA-certified guides · permits sorted · 5,000+ treks since 1998. $800 pp Plan this trek

Get the free Nepal Trek Insider Guide

Free guide Permits, costs, seasons and routes — the essentials we send every traveller, plus a free, no-obligation trip quote. ↑ Swipe up Read the full report and grab the free Nepal Trek Insider Guide — or ask our Pokhara team for a tailored, no-obligation quote. Read more & get the free guide Plan my trip — free quote Browse Langtang Valley Trek — 7 Days