Tonnes of ice masses moved downslope and buried three Sherpa guides underneath, on Wednesday morning, in the season’s first accident on the world’s tallest peak—Everest.

Lakpa Norbu Sherpa, the Everest base camp coordinator of the Himalayan Rescue Association, told the Post from the base camp that the massive ice sheet of more than 50 metres tumbled down the mountain, below Camp 1 at 5,700 metres, and buried three guides.

The possibility of finding the missing climbers alive is “very slim”, he said.

“They are buried five to six metres underneath. It’s not possible to launch a search mission because the risk of an avalanche is still ongoing,” said Norbu Sherpa, who is also a long-line rescue specialist.

“We have traced the spot but it’s not possible to go there. The ice sheets are as big as houses. It’s not possible to dig either,” he said.

The accident took place at 9:30 am when the team of around 25 high-altitude guides were climbing above the Khumbu Icefall to prepare the route from Camp 2 to the summit, said Norbu.

“It’s not that they fell into crevasses. They are buried under the ice masses in the Khumbu Icefall, the most dangerous section of Everest,” said Norbu.

Bigyan Koirala, an official at the Department of Tourism, said that the rescue efforts are on.

A chopper has made three rounds in the area already, said Koirala.

He said the rescuers would use the Recco detector and avalanche transceiver, devices used to search and locate people buried under snow.

But, according to Norbu, although they know the exact location of the incident site it’s impossible to go there either by chopper or on foot.

“More avalanche is likely due to the movement of the massive snow mass.”

The icefall doctors mobilised by the Sagarmatha Pollution Control Committee, an agency authorised to fix ropes and ladders up to Camp 2 on Everest, had completed preparing the route from base camp through the Khumbu Icefall to Camp 2 last Thursday.

Imagine Nepal Trek and Expedition has won the bid to prepare the route from Camp 2 to the summit.

The route-fixing team was led by Dawa Gyalje Sherpa. They moved towards base camp on April 5 to prepare the route.

The passage through the Khumbu Icefall, the route that leads to the world’s tallest peak, is so notoriously dangerous that even experienced Sherpas hesitate to move when the sun shines. The Khumbu Icefall stretches from 5,500 to 5,800 metres and lies just above the Everest base camp.

The Khumbu Icefall, a river of ice—a kilometre or so, is normally crossed during the night or early morning with climbers using headlamps.

Normally, the route is crossed between 3am and 5am, the time when the ice blocks and the hanging glaciers are stable and avalanche risks are low.

On April 18, 2014, an avalanche resulting from a falling serac buried 16 sherpa guides in the Khumbu Icefall which led to the cancellation of the season’s expeditions. Thirteen bodies were recovered within two days, while the remaining three were never recovered. This was the same icefall where the 1970 Everest disaster had taken place.

In April 2015, an earthquake triggered an avalanche on Everest, killing 22, the deadliest incident on the mountain on record.

The Himalayan Database has recorded 44 deaths on the Khumbu Icefall from 1953 to 2016.