Nanda Devi in the Indian Himalayas. Rescue teams could take three days to reach the climbers’ last known camp.

Four British climbers among group of eight missing in Himalayas

Rescuers are searching for four people from Britain, two from the US, an Australian and an Indian who went missing while climbing a mountain in the Himalayas after reports of a heavy avalanche.

They failed to return to base camp following their attempt to reach a summit at 6,477 metres (21,250ft) altitude on Nanda Devi, India’s second-highest mountain, on a previously unclimbed route after reaching 4,870 metres on 22 May.

Indian authorities sent out a search team of up to 20 people on foot on Saturday, but they were not expected to reach the amateur climbers’ last known camp for three days, and officials said the harsh weather hampered their progress.

An air force helicopter will be used for aerial reconnaissance on Sunday, but it may not be able to land in the difficult terrain.

“We always have hope, but to be practical, we have to be prepared for bad news,” Amit Chowdhury, an Indian Mountaineering Foundation spokesman, said on Saturday.

The eight were part of a larger contingent of 12 climbers who began their ascent on 13 May from the village of Munsiyari, in the hill state of Uttarakhand in northern India, near the western Nepal border.

The group said it had trekked into the heart of the Nanda Devi sanctuary “with the ambition of summiting a virgin peak”. The trip was expected to take about 24 days.

According to an update on 22 May, the group had reached their second base camp at 4,870 metres and were due to make a summit attempt on an unclimbed peak at 6,477 metres.

However, by last Saturday – 25 May – the expedition’s British deputy leader, Mark Thomas, had returned to the second base camp with three others.

He was in radio contact with the group of eight that pushed higher but when Thomas did not hear from the group by last Sunday he went up to look for them. He reportedly found a single unoccupied tent. There was evidence of a large avalanche beyond that.

It was unclear if the climbers went missing during their ascent or descent, while the cause of their disappearance remains unknown.

The British-based mountain guide Martin Moran, who owns the trekking company Moran Mountain, was leading the group, which was also believed to have included a 47-year-old Australian woman, Ruth McCance.

Mark Charlton, the president of the British Association of Mountain Guides (BMG), said in a post on the organisation’s Facebook page that Moran had been leading six clients and an Indian national.

“The BMG is assisting where possible and is in contact with the Indian authorities,” he said. “At the moment this is all the information we have as communication is very difficult.”

A post on the Moran Mountain Facebook page said the company was working with authorities and the BMG to gather information about the expedition team.

A spokeswoman for the Foreign Office said: “We are in contact with the Indian authorities following reports that a number of British nationals are missing in the Indian Himalayas. We will do all we can to assist any British people who need our help.”

A spokesperson from Australia’s Department of Foreign Affairs and Trade said it was “providing consular assistance to the family of an Australian that may be among a group of trekkers missing in the Nanda Devi area of India”.

The news follows a number of deaths in the Himalayas this year, with at least 11 people – including a British man and an Irish man – reported to have died on Everest in the past two weeks amid overcrowding and poor weather.

There have reportedly been a record 381 permits issued to scale Everest for this climbing season, and there have been calls for tighter vetting of people’s mountaineering experience.