Was it the weather?

Fresh Findings

For close to 90 years, a veil of mystery remained on how George Mallory and Andrew Irvine disappeared from the face of the earth when the Everest summit was a few hundred meters away. Nobody knew what happened to the two young mountaineers till recently when Mallory’s body was finally discovered. Even less is known on what killed them.

Now analysing weather records maintained by the Everest expedition teams and comparing them with weather maps produced by the Indian Meteorological Department then, a team of Canadian and Indian scientists have come out with an answer to that question. And one of the culprits behind their death, they claimed, is a common Indian weather phenomenon, seen widely in the monsoon season.

The 1924 British Expedition represented the culmination of early attempts to climb Mount Everest. The expedition was notable for the two summit attempts that took place in early June of that year. The team tried the more treacherous North Col route to reach the summit. After witnessing hostile weather in May, attempts to scale the summit were made in the first week of June.

Mallory and Irvine made the second attempt using supplementary oxygen after the first attempt failed. They departed Camp IV on June 6 and spent the June 7 night at Camp VI with the intention of leaving for the summit next day.

Another mountaineer Noel Odell who was to climb in support of the advanced party left Camp V on the morning of June 8 in anticipation of meeting the returning climbers at Camp VI that evening. Around noon there was a clearing of the clouds when Odell saw the whole summit ridge and the Everest peak and Mallory and Irvine who were climbing over an obstacle along the ridge. That was the last time, when the duo was seen alive.

Later many artefacts from Mallory and Irvine’s climb were recovered with the most significant being the discovery of Mallory’s body in 1999. Despite the discoveries, not much is still known about their climb, including whether they were successful in their
summit attempt.

“The disappearance of Mallory and Irvine is one of the most enduring mysteries of the 20th century, yet throughout the debates surrounding their disappearance the issue of the weather has never really been addressed,” said GWK Moore from the University of Toronto.

Analysing the weather, a first

Though the 1924 expedition generated lots of meteorological data, Moore along with John Semple, Chief of Surgery at Women’s College Hospital in Toronto and Dev Raj Sikka, former director of Indian Institute of Tropical Meteorology, Pune claim to have analysed it for the first time systematically. During the summit attempt, they found, there was a massive drop in barometric pressure at the base camp of approximately 18 milli bar.

Mount Everest is so high that the low barometric pressure near its summit places humans extremely close to the tolerance limit for hypoxia. It is likely that this drop in pressure would have resulted in an increase in their hypoxic state. The situation was further compounded by heavy weather including a blizzard, thanks to Western Disturbance.

“It was pre-monsoon season. There were moisture incursions in the eastern part of India, which were lifted by the Western Disturbance causing heavy snowfall and blizzard, which the climbers encountered,” Sikka told Deccan Herald. Compounded by the effects of hypoxia, fatigue, and extreme cold, Mallory and Irvine would have been at the limit of their endurance as they moved along the Northeast Ridge of Everest in the midst of a severe blizzard associated with the onset of monsoon in India.

Their situation would have been aggravated by the fact that they most likely ran out of supplemental oxygen on the afternoon of June 8 resulting in an increase in hypoxic state. Cognitive impairment during descent brought on by hypoxia is the most common cause of death on Mount Everest, the researchers reported in the August issue of Weather published by the Royal Meteorological Society.

An unusual western disturbance

“Even though WD is known for 100 years, that was a very unusual WD, which could not be anticipated. Also the pressure drop was huge,” Sikka said.

Additional support for this conjecture comes from the documented observations of heavy precipitation in the vicinity of Mount Everest on June 8 and 9 – also triggered by the WD. Odell mentioned that the blizzard on June 8 lasted approximately two hours and that strong winds persisted through to the 10th before they started to relent.

“Mount Everest is so high that there is barely enough oxygen near its summit to sustain life and a drop of pressure of only four millibar at the summit is sufficient to drive individuals into a hypoxic state,” said Semple who is also an experienced mountaineer.

A similar 1996 incident comes as an indirect proof of the new theory. In that event, the stormy weather was of a short duration and the cessation of convection was followed by an extended period of high winds near the summit that was shown to be associated with the presence of a jet streak. The authors conclude that with the additional stresses they were under with extreme cold, high winds and the uncertainly of their route, the pressure drop and the ensuring hypoxia contributed to the duo’s death. May be this closes the chapter on Mallory and Irvine.