AS AN explanation for the deaths of eight climbers on Mount Everest in 1996, it reads like a nasty ending in a nursery rhyme. According to a new analysis of the weather, the mountaineers lost their lives when the sky fell down.
The victims were members of a group of 26, and perished when a seemingly calm day turned stormy. Kent Moore, a physicist from the University of Toronto in Canada, thinks this happened when the stratosphere sank down onto the mountain's summit.
Usually Everest's 8848-metre peak sits just below this layer of the atmosphere. But on 10 May that year there were two streams of very fast-flowing air called jet streaks moving over the mountain. Moore suggests that these would have pushed the boundary down, causing the pressure and oxygen level to drop dramatically.
During a similar event in 1998, there was a temporary weather station near the top of the mountain which recorded a sudden fall in pressure of 16 millibars. Such a drop is significant where the air is already very thin. On top of Everest, it is equivalent to raising the mountain by 500 metres, and would have instantly cut the amount of oxygen the mountaineers were breathing by about 14 per cent.