Sunday, January 02, 2005

Stratosphere on Everest -- more

Telegraph | Connected | Sky 'fell in' on Everest

Google found me this:
The eight climbers killed on the single deadliest day on Everest may have been victims of the "sky falling in", according to a study.

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.

Normally Everest's summit lies just below the atmospheric layer. But on May 10, the day of the disaster, there were two fast-flowing air streams, called jet streaks, moving over the mountain.

Dr Kent Moore, a physicist at the University of Toronto in Canada, believes these would have pushed the stratosphere boundary down with catastrophic results.

During a similar event in 1998 a temporary weather station near the top of Everest recorded a sudden fall in pressure of 16 millibars.

"Such a drop is significant where the air is already very thin," New Scientist reports today. On Everest's summit, it would have been the equivalent to raising the mountain by around 500 yards. It would have instantly cut the amount of oxygen available to the mountaineers by around 14 per cent, Dr Moore believes.

At the summit the air already contains only a third of the oxygen it holds at sea level. The eight were members of a group who were climbing without supplementary oxygen.

Conditions had been good, with the sky free of clouds and the wind light. However, by around 4pm, the "death zone" was engulfed by storms, winds of up to 90mph and temperatures that crashed to minus 40C.

Within 24 hours, eight out of 30 climbers on the mountain were dead. They included Scott Fischer, from Seattle, and Rob Hall, from New Zealand, the expedition leaders.

The story of that day was famously told in a magazine by Jon Krakauer; he later turned the story into a captivating book. His version of events has been disputed, unsurprisingly.

I have a slight connection to the expedition -- one my medical school classmates was the physician in Krakauer's book. (Krakauer misspelled my classmates name, I don't know if that was deliberate.)

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