It turns out that, for the expedition that lost so many people on Everest eight years ago, Chicken Little was right.

An analysis of weather patterns in May 1996 suggests the mountaineers died when the stratosphere sank to the level of the summit, 29,000ft above sea level.

The freak weather caused pressure and oxygen levels to plunge within the “death zone” – the area above 26,000ft where the oxygen is extremely thin.