Mike Searle is a professor of earth sciences at the University of Oxford.
The Hillary Step, a rocky outcrop at 8,770m, just beneath the summit of Everest (8,850m), has finally succumbed to gravity and partially collapsed. At least it has according to mountaineer Tim Mosedale, who climbed the mountain this year. His claim has been refuted by the chair of the Nepal Mountaineering Association, however, sparking a debate which looks set to rage for some time yet. The definitive answer, after all, is located only a few metres short of the top of the world.
Named after Sir Edmund Hillary – the first to reach the summit of Everest, with Sherpa Tenzing Norgay, in May 1953 – this rocky structure certainly has a noble heritage in mountaineering circles. It is the last major obstacle encountered on the South Col route before reaching the summit.
But it also famed in geological circles. It is, or was, formed of a resistant limestone band along the base of the Qomolangma Formation which dates back to the Upper Cambrian or Lower Ordovician age. These rocks feature tiny remnants of crinoid ossicles (stems of sea lillies) that originally lived in a shallow tropical ocean 450m years ago and can now be found on the summit of Everest.
If the Hillary Step has indeed collapsed, the rockfall will have altered the standard route to the top. And this may result in increasing congestion as parties queue up to get to the summit during the brief period of stable, pre-monsoon climbing conditions in May. As Mosedale told Planet Mountain:
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…