Mountaineers are reporting that Mt Everest's famous Hillary Step, named after Sir Edmund Hillary, has collapsed, most likely due to Nepal's 2015 earthquake.
"It's official - The Hillary Step is no more. 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," British mountaineer and commercial expedition leader Tim Mosedale posted on the Everest Expedition Facebook page.
First tackled by Sir Ed and Tenzing Norgay in 1953 and so named after him, the Hillary Step was the final major obstacle on the Everest ascent.
It was a 12-metre-high rock barrier, which often caused long wait times as climbers waited for the path to be free.
Mr Mosedale told planetmountain.com the step had been destroyed, leaving "rubble and debris".
"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. The Hillary Step often formed a bottleneck but some years they fixed an up and a down rope," he said.
"In the current state it would be difficult to safely negotiate down where the step used to be on account of the huge unstable rocks that are perched on the route."