At least four people have been left injured after an avalanche in a popular ski resort in the Swiss Alps, and reports indicate that as many as 10 people are still trapped.

Eight helicopters, 12 dogs and more than 240 police, rescuers and soldiers worked into the night to find any more people buried in the snow on a marked slope in Crans-Montana.

“Rescuers arrived very quickly on the scene, they rescued four injured people including one whose life is in danger, and three were injured more superficially,” Valais cantonal police commander Christian Varone told a news conference.

“Witnesses told us there could be more people buried under the snow, that is why we are pursuing the search with considerable means.”

“We are shocked and hope for good news about these people,” said Nicolas Feraud, president of Crans-Montana’s municipal government. He told local paper Le Nouvelliste he thought “between 10 and 12 people” could still be trapped.

Abandoned Alps Ski Resort in South Korea Show all 15 1 /15 Abandoned Alps Ski Resort in South Korea Abandoned Alps Ski Resort in South Korea An overview of the abandoned Alps Ski Resort, a former holiday destination in South Korea’s far north-east close to the Demilitarized Zone that divides the peninsula AFP/Getty Abandoned Alps Ski Resort in South Korea Ski boots piled up in a former restaurant. The resort is close to the city of Sokcho AFP/Getty Abandoned Alps Ski Resort in South Korea An accommodation block in the resort. The Alps Ski Resort was one of the country’s first winter sports destinations AFP/Getty Abandoned Alps Ski Resort in South Korea A derelict swimming pool, in the resort which abruptly shut its doors in 2006 AFP/Getty Abandoned Alps Ski Resort in South Korea Skis and golf carts left in a facility. The Alps Ski Resort attracted tens of thousands of skiers a year when it was open AFP/Getty Abandoned Alps Ski Resort in South Korea Closed ski-hire shops. South Korea has spent $800m (£562m) on the sporting facilities for next month’s Winter Olympics AFP/Getty Abandoned Alps Ski Resort in South Korea Rows of chairs in a ballroom. The IOC has expressed concern over the absence of future plans for the new facilities in Pyeongchang AFP/Getty Abandoned Alps Ski Resort in South Korea Closed ski-hire shops and bars. The IOC now says the legacy of next month’s games should be addressed as a priority AFP/Getty Abandoned Alps Ski Resort in South Korea Abandoned ski lifts close to the Alps Ski Resort AFP/Getty Abandoned Alps Ski Resort in South Korea The desolate Alps Ski Resort lies in an area which receives the heaviest snowfall in the country AFP/Getty Abandoned Alps Ski Resort in South Korea The main lobby of the Eighties-era visitor centre AFP/Getty Abandoned Alps Ski Resort in South Korea Crockery in an abandoned restaurant. For 250 residents, livelihoods were lost when the resort closed AFP/Getty Abandoned Alps Ski Resort in South Korea A faded poster in an office. Many of the new facilities in Pyeonchanng will be torn down after use AFP/Getty Abandoned Alps Ski Resort in South Korea Residential blocks and hotels in the resort, empty for over a decade. The future is uncertain for many of the permanent structures built for the coming Olympics AFP/Getty Abandoned Alps Ski Resort in South Korea Oh Geum-Sik standing in his ski rental shop in the empty resort AFP/Getty

He said the avalanche was 840 metres (yards) long and 100 metres wide, with 400 meters of heavy snow hitting the piste.

An investigation as been opened by the Valais Public Prosecutor to determine the cause of the avalanche.

The avalanche, in mid-afternoon, came after a week of warmer temperatures began melting heavy snow. But the Swiss Institute for Snow and Avalanche Research said the danger for the area had been only at level two on a scale of five on Tuesday.

Prosecutor Catherine Seppey said that an investigation had been opened. “There are two hypotheses. The first is that several skiers set off the avalanche. The second hypothesis is it was a spontaneous avalanche due to climatic conditions, and in that case it will be a question of determining responsibilities and problems of security,” she said.

Support free-thinking journalism and attend Independent events

Philippe Magistretti, president of the Crans-Montana ski lift company, told Reuters by telephone that army personnel who were in the resort had joined the rescue effort.

“The amount of snow is incredible, two metres deep and 300 metres long. It’s a spring avalanche which is very compact,” the Nouvelliste quoted one unnamed rescue worker as saying. Rescue dogs had not found anyone during a first search, he added.

The avalanche coincided with school holidays in some cantons, including Geneva, as well as overseas. Britain’s Blackheath High School tweeted that all its students on a ski trip in the area were safe.

The resort is scheduled to host two World Cup women’s races this weekend.