Nepal’s mountain guides are accustomed to working where few others can go — on narrow ridges, beneath collapsing ice walls and high in the thin air of the death zone.

On Saturday, three of them found themselves facing a very different kind of danger.

Instead of climbing through snow and ice, they entered a dark tunnel filled with thick mud and debris, searching for signs of life after catastrophic flooding devastated the Trishuli river system.

The guides had spent four days asking to be allowed to help.

When they were finally called in at the request of the Chilime hydropower project, they took the risk without hesitation.

Ashis Gurung and Jenjen Lama, an aspirant mountain guide who has recently completed his IFMGA training, entered the tunnel while Dorjee Sherpa remained outside.

The other members of the rescue team, who were not deployed in the field, were Sabin Thakuri, who remained on standby at Kathmandu Airport; NNMGA coordinator Tul Singh Gurung; and Pasang Tendi Sherpa, coordinator of the Nepal Mountaineering Instructors Association.

The duo progressed about 120 metres into the darkness, wading through deep sludge and debris, before recovering a camera bag. But their advance was eventually stopped by a huge accumulation of thick mud that had completely blocked the passage.

They found no survivors and no way through.

“We first tried using snow boots to stop ourselves from sinking,” Lama said. “When that did not work properly, Ashis Dai (Ashish Gurung) came up with the idea of using wooden planks.”

The men used the planks to spread their weight over the unstable sludge as they moved deeper into the tunnel.

Mountain guides, Lama said, were trained to recognise the dangers of confined and oxygen-poor environments.

“Because we work in the death zone, we know when oxygen levels are starting to deplete and what precautions need to be taken,” he said.

But even after moving 120 metres into the tunnel, the guides could find no outlet. The sludge was deep and the passage ahead completely blocked.

The operation offered a glimpse of the specialised skills possessed by Nepal’s mountain guides — expertise in difficult terrain, rope systems and high-risk rescue environments that can be applied far beyond the country's mountaineering and adventure tourism industry.

Yet the mission also highlighted what the guides say has been a frustrating failure by authorities to make full use of those skills during the disaster response.

The team from the Nepal National Mountain Guide Association had been standing by for four days, repeatedly asking for an opportunity to join search and rescue operations. Some members had been preparing to leave for Manaslu for the autumn climbing season but volunteered instead to support the national emergency effort.

Their original proposal was to use fixed ropes to reach survivors stranded on steep and inaccessible terrain and, where necessary, conduct helicopter long-line rescues.

“Due to the difficult terrain, steep surroundings and confined access, evacuating a large number of people individually by small helicopters may be difficult, time-consuming and potentially risky,” Lama said in an earlier appeal.

He argued that fixed rope systems could allow rescuers to reach places where helicopters could not land.

“Please use experienced experts and rescuers where they are actually needed,” he later wrote on Facebook. “We need the right people in the right places — not just rescuers being taken in helicopters to observe the situation and take photos or videos.”

Tul Singh Gurung, president of the Nepal National Mountain Guide Association, had also submitted a formal request to authorities asking that the country's internationally trained mountain guides be deployed in the rescue operation.

Saturday’s mission had initially been planned as a helicopter long-line access and rescue operation because heavy mud around the tunnel was expected to make landing impossible.

The NNMGA team had prepared technical anchors and equipment to access the site by long-line if necessary.

But conditions had improved sufficiently for the helicopter to land near the tunnel entrance, allowing the guides to reach the site directly.

After their search, the team concluded that human effort alone could not clear the tunnel.

According to IFMGA mountain guide Ashish Gurung, the mud reached up to our chests, making further progress extremely difficult. Because of these conditions, we were unable to reach the completely blocked section of the tunnel.

Excavators and pumping equipment will be needed to remove the accumulated mud and debris before rescuers can search deeper inside, the guides said.

The team returned to Kathmandu after completing the assessment and said it remained ready to deploy again.

For Lama, the day brought some recognition after days of frustration.

He said the Prime Minister’s Office called after the operation to acknowledge the mountain guides' expertise — and admitted that officials had not previously understood the range of skills available to them.

“Now it feels good to know that our work is being recognised,” Lama told Everest Chronicle.

But he said the experience had also exposed a deeper problem.

“It is very disappointing to see that the right and experienced people are still not being utilised where they are most needed.”

The team involved in Saturday’s operation comprised IFMGA mountain guides Ashis Gurung and Dorjee Sherpa, alongside aspirant mountain guide JenJen Lama. Aspirant mountain guide Sabin Thakuri remained on standby in Kathmandu.

The NNMGA said it was ready to provide technical terrain search and rescue, rope rescue, mountain rescue and helicopter long-line rescue in coordination with the authorities.

For now, some of Nepal’s most experienced rescuers have returned from the mountains to wait for another call.