Hotelier Sherap Gurung of Lokpa, the gateway village and permit checkpoint for the popular Tsum Valley trekking area in northern Gorkha district, woke early on Sunday to a growing rumble from the Syarkhola stream below his house. When he stepped outside at dawn, he saw water surging through the stream with an unfamiliar roar. He rushed inside, woke his wife and children, and alerted the tourists staying at his hotel before leading everyone to higher ground.

Footage posted on social media shows a torrent of black mud and rocks hurtling downhill, destroying structures as residents scream, flee their homes and scramble for safety.

The disaster comes less than two months after the devastating Bhotekoshi floods, which killed hundreds of people and left thousands missing. The back-to-back disasters have raised serious questions about the safety of settlements along Nepal’s river corridors fed by water from the high Himalayas, and the risks faced by communities living downstream. 

Preliminary assessments suggest that the flood originated in Syarkhola, a tributary of the Budhigandaki, after a landslide reportedly blocked the Ungilung stream, which feeds into it. When the blockage gave way, a surge of water and debris swept into the Budhigandaki, devastating settlements along the river and sweeping away bridges and trekking trails.

Emergency rescue operations began early in the morning, with helicopters and security personnel deployed to flood-affected areas. Authorities also issued warnings urging people to remain on high alert along the low-lying river corridors, including areas downstream towards the Trishuli River.

“We had never heard such a sound before. It reminded us of the August 26 Bhotekoshi flood, and we realised this was a flood,” said Sherap. “We returned home only after daylight.”

He estimated that the Syarkhola had been blocked and released at least six times.

“When the stream is blocked, there is no sound. When the water starts flowing again, it roars loudly. We stayed in fear, wondering what would happen next,” he said.

Sherap recalled witnessing a flood in the Syarkhola some 25 to 30 years ago but said he had never seen the stream surge with such violence as it did on Sunday.

“I never imagined a flood like this could happen,” he said. “I never knew this very stream could swell to such a size.”

The National Disaster Risk Reduction and Management Authority, under the Home Ministry, has provisionally attributed the flooding to landslide debris from the Ungilung stream, which blocked the Syarkhola before the accumulated water burst through. The exact cause, however, remains unconfirmed.

Police said five people were missing following the disaster. Sonam Lama, 65, his wife Memmo Aji Lama, 59, Som Bhuti Lama, 66, Karma Lama, 73, and Dorje Lama, 41, of Chumchet in Chumnubri-6, went out of contact after the flood. They had gone to graze sheep and were staying in a shed near the Ungilung stream.

“We sent villagers to look for them, but the shed itself cannot be seen. The landslide is still active, so it is dangerous to approach,” said Sherap.

Assistant Chief District Officer of Gorkha Netra Prasad Sharma confirmed that the five people were missing.

Preliminary assessments indicate that 45 houses have been completely destroyed and 27 partially damaged in Ghattekhola, Salleri, Paiyun and Jagatbagar in Chumnubri, as well as Machhakhola in ward 5 of Dharche Rural Municipality. Two motorable bridges, two suspension bridges, three hydropower projects and 34 livestock sheds have also reportedly been damaged.

Authorities are still collecting details to establish the full extent of the destruction.

Residents in several settlements fled their homes after receiving telephone warnings from people living upstream.

Ganesh Karki of Jagatbagar said he spent the day in the forest after hearing that a flood was approaching.

“We received a call early in the morning warning us about the flood. The river rose until it reached the settlement, and we left our homes,” he said.

Karki and other residents took shelter about 500 metres uphill. “We never imagined a flood of this size. The water surged for about 15 minutes and then stopped, repeatedly throughout the morning. We are afraid to return home at night.”

Ram Kumar Gurung, ward chair of Chumnubri-3, said the flooding had terrified residents and forced them to abandon their homes.

The Nepali Army deployed four helicopters to rescue people stranded by the flood and moved 95 people to safer locations, according to the army. Narayan Prasad Sapkota, administrative chief of Chumnubri Rural Municipality, separately said 96 people had been rescued from the rural municipality on Sunday.

The destruction of bridges and trails has severed northern Gorkha's road and foot-trail connections, leaving settlements dependent on air transport and making the movement of people and supplies difficult.

The approach to the motorable bridge at ward 9 of Arughat Rural Municipality linking Gorkha and Dhading districts, was swept away on the Gorkha side. Another bridge connecting Manbu in ward 2 of Arughat with Soti in ward 3 was also destroyed.

The flood washed away the suspension bridge connecting Nagchet and Philim in ward 3 of Chumnubri, as well as the bridge linking Machhakhola in ward 5 of Dharche with Kerauja. A cantilever bridge at Sardibhir, built after the April 2015 earthquake, was also destroyed, severing the only foot-trail connection between Chumchet and Chhekampar.

“The river has cut through the road from Dobhan, and the routes around Jagat and Salleri have been completely damaged,” said Sapkota. “The entire rural municipality is now cut off, with air travel the only remaining way to reach it.”

Officials planned to explore alternative routes on Monday after prioritising rescue operations on Sunday.

The flood also damaged Bikas Basic School in Ghattekhola. According to Sapkota, 31 houses were swept away in Chumnubri alone.

Tourists stranded

Tourists visiting the Manaslu region have been stranded along trekking routes after bridges and trails were washed away. The Manaslu Conservation Area Project said visitors remained at the places where they had spent Saturday night and were safe.

“Tourists are staying where they were. They are safe,” said Bhuwan Ojha, the project's information officer.

Around 115 tourists were in Jagat and 40 in Lokpa, he said. The route from Jagatbagar to Philim has been badly damaged, while the trail towards Tsum Valley has been closed to trekkers.

September to November is considered the best season for trekking in the Manaslu region, as the monsoon subsides, skies clear, and mountain views improve. The flood struck during this peak trekking season when visitor numbers were high, raising concerns about access to food, supplies and emergency services for those unable to continue their journeys.

The disruption could also affect local businesses that depend on trekking tourism during the peak season.

Hydropower projects damaged

Three hydropower projects have also suffered damage from the floods.

The 341-megawatt Budhigandaki semi-reservoir project, which is under construction in Salleri, sustained damage as floodwaters swept away equipment and damaged the construction camp.

The 24.5-megawatt project at Dobhan suffered damage to its camp and Bailey bridge, while the access road to the 16-megawatt Machhakhola hydropower project was damaged.

The destruction has added to the immediate challenges facing residents and authorities, who must locate the missing people, assess damage to infrastructure and restore access to isolated settlements.

With bridges destroyed, trekking routes blocked and the full extent of the damage still unknown, northern Gorkha faces an urgent struggle to reach stranded communities, deliver essential supplies and reconnect settlements cut off by the flood.