A catastrophic flash flood tore through Nepal's Rasuwa District on August 26, sending a surge of water, sediment, and boulders down the Bhote Koshi and into the Trishuli River system. The wave hit the Rasuwagadhi–Timure border area and Syabrubesi before continuing south toward Nuwakot and Dhading. Downstream at Galchhi, the Trishuli River rose roughly nine meters in just 30 minutes.

As of the latest count, 165 bodies have been recovered in Nepal and at least 800 people remain missing, including more than 500 foreign nationals. The disaster also struck the Chinese side of the border near Gyirong, and downstream Indian states, Bihar, Uttar Pradesh, and Uttarakhand, have begun evacuations as authorities monitor the risk of the surge traveling into the Gandak River basin.

The precise trigger is still under investigation, but preliminary assessments point to a large volume of ice and rock entering a tributary of the Bhote Koshi, possibly following a partial glacier collapse. An upstream debris blockage remains in place and could still fail, raising the risk of a second flood.

Risk Level: Critical | Recommended Posture: Suspend all nonessential travel to Rasuwa, Nuwakot, and Dhading districts and the Rasuwagadhi-Gyirong corridor. Initiate immediate personnel accountability for all staff in or transiting the Bhote Koshi-Trishuli river corridor. Do not authorize movement on affected roads, bridges, or border crossings without independently verified access and safety clearance.