On 11 October 2026, sudden surges of black mud and rocks hit settlements along the Budhi Gandaki River in northern Gorkha. A technical assessment by the National Disaster Risk Reduction and Management Authority (NDRRMA) explained what happened.
Cause (NDRRMA assessment)
- A large landslide of snow, water and glacial debris at about 5,500–6,000 m, in the upper Ungdilung Khola, between Chamar Himal and Syerangi Himal
- Weak rock of the Tibetan Tethys Himalaya on the slope
- Debris piled up where Ungdilung Khola meets Syar Khola, blocking and then releasing water again and again
- The flow carried so much soil that it behaved like a dense mudflow (debris flow), not a normal flash flood
- The Department of Mines and Geology estimated the landslide released energy equal to a magnitude 3.5 earthquake
Impact
- At Salleri, the biggest surge (about 20–25 m high) arrived around 6:30 am and swept away a hydropower camp
- Buildings were damaged at Jagat; bridges over Soti Khola and Budhi Gandaki were damaged
- The Nepali Army told a parliamentary committee (30 Oct) that 1,025 people were evacuated, six bridges were destroyed and 91.5 km of road was blocked
Lessons
The Army called for a single chain of command in disaster response and early-warning systems for 45 high-risk glacial lakes. In Nepal, disaster work is led by the NDRRMA under the Disaster Risk Reduction and Management Act, 2074.
Practice MCQs
1. The October 2026 Budhi Gandaki flood occurred in which district?
a) Lamjung b) Gorkha c) Dhading d) Manang
Answer: b) Gorkha
2. According to NDRRMA, the flood was mainly caused by:
a) Dam failure b) Heavy monsoon rain only c) A landslide of snow, water and glacial debris d) An earthquake
Answer: c) A landslide of snow, water and glacial debris
3. Disaster management in Nepal is governed by the Disaster Risk Reduction and Management Act of:
a) 2064 b) 2071 c) 2074 d) 2078
Answer: c) 2074
4. A flow carrying very high amounts of soil and rocks is called a:
a) Flash flood b) Debris flow / mudflow c) Tsunami d) Avalanche
Answer: b) Debris flow / mudflow
Related
Sources: The Himalayan Times (13 Oct 2026, NDRRMA report); The Kathmandu Post (12 Oct 2026); Nepal News evening briefing (30 Oct 2026).
Why this matters for Lok Sewa
- Disaster management is a regular subjective topic for Nayab Subba and Section Officer, and NDRRMA is often asked about.
- The difference between a debris flow and a flash flood is a good point for long answers on climate risks.
Quick practice questions
- Which authority assessed the Budhi Gandaki flood? Answer: The National Disaster Risk Reduction and Management Authority (NDRRMA).
- The Budhi Gandaki flood of October 2026 hit which district? Answer: Gorkha.