The Hillary Step, a rocky outcrop on the main climbing route up Mount Everest, has collapsed, according to climbers who made the top of the mountain this weekend. “It's official - The Hillary Step is no more," wrote mountaineer and expedition leader Tim Mosedale in a post on Facebook. Experts including Mosedale believe the collapse may make the mountain more dangerous to climb.

The feature, named for Sir Edmund Hillary (the first person to successfully climb the mountain with his partner Tenzing Norgay in 1953), famously represented the last obstacle before the summit.

"Bottlenecks can force climbers to spend longer than planned in the 'death zone' above 8,000 metres, where the human body is slowly dying even with supplementary oxygen."

Some 12 metres high, the Hillary Step required mountaineers to do some actual climbing and had been responsible for some dangerous bottlenecks in the past.

However, two fixed ropes and years of accumulated knowledge of climbing the Step had alleviated the problem of traffic somewhat in recent years, and Mosedale believes the collapse may in fact make the section trickier, and the bottlenecks worse.

He wrote: "Not sure what's going to happen when the snow ridge doesn't form because there's some huge blocks randomly perched hither and thither which will be quite tricky to negotiate".

In an interview with climbing site Planet Mountain, he added: “It's easier going up the snow slope (and indeed for inexperienced climbers and mountaineers there's less 'climbing' to be done making it much easier for them). However it's going to form a bottleneck."

Crowding on Everest is a hugely controversial issue. Slow-moving traffic can force climbers to spend longer than planned in the “death zone" above 8,000 metres, where the human body is slowly dying even with supplementary oxygen. A bottleneck at the Hillary Step was one of the factors which contributed to the death of eight climbers on Everest during the 1996 disaster (the subject of the recent Hollywood blockbuster Everest).

The fear is that further crowding on the section because of the collapse of the Hillary Step could present serious problems for Everest expeditions in the future.

It’s suspected that the shape of the rocky outcrop was altered irrevocably by the massive earthquake that devastated Nepal in 2015.

Photos posted last year by the American Himalayan Foundation (above) appeared to show the Step had changed, but due to the amount of snow it wasn’t confirmed until Mosedale’s party - among the first commercial expeditions to summit Everest during a recent weather window - returned to Base Camp and began uploading photos.

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