Cho Oyuचोयु

Cho Oyu (Tibetan for 'Turquoise Goddess') is the sixth-highest mountain in the world, rising to 8,188 metres (26,864 feet) above sea level. It stands on the China–Nepal border, straddling the boundary between the Tibet Autonomous Region of China and Koshi Province of Nepal. The mountain is the westernmost major peak of the Khumbu sub-section of the Mahalangur Himal, the same range that contains Mount Everest, Lhotse and Makalu, and lies roughly 20 kilometres (12 miles) west of Everest itself. Its topographic prominence is about 2,340 metres (7,680 feet).

Immediately to the west of the summit lies the Nangpa La, a glaciated pass at 5,716 metres (18,753 feet) that has for centuries been a principal trading route between the Khumbu region of Nepal and Tibet. The relatively gentle terrain on the northwest, or Tibetan, side of the mountain — including road access that reaches close to base camp — has long made Cho Oyu unusually accessible by the standards of an eight-thousander, and it is this approach that almost all commercial expeditions use.

The mountain's recorded height has shifted over time as surveying improved. Early measurements gave about 26,750 feet (roughly 8,150 m), which initially ranked it as the seventh-highest peak on Earth; a 1984 estimate of around 8,201 m moved it to sixth. New measurements made in 1996 by the Government of Nepal Survey Department together with the Finnish Meteorological Institute, prepared for the Nepal topographic map series, established the now-standard figure of 8,188 m — close to the figure of about 8,189 m (26,867 feet) that Edmund Hillary had cited in his 1955 book High Adventure.

The first serious approach to Cho Oyu came in 1952, when a British reconnaissance expedition led by Eric Shipton — and including Edmund Hillary, Tom Bourdillon and George Lowe — examined the mountain partly as preparation for the following year's Everest attempt. The party reached a high point on the mountain before turning back, deterred by technical difficulties, avalanche danger and reports of Chinese troops in the area.

Cho Oyu was first climbed on 19 October 1954 by an Austrian expedition, with Herbert Tichy and Joseph Jöchler reaching the summit alongside the Sherpa Pasang Dawa Lama via the northwest ridge. It was the fifth eight-thousander to be climbed, following Annapurna (1950), Everest (May 1953), Nanga Parbat (July 1953) and K2 (July 1954). The ascent was a landmark for lightweight mountaineering, and until Reinhold Messner and Peter Habeler climbed Everest without supplemental oxygen in 1978 it remained the highest summit reached without bottled oxygen.

Subsequent decades brought a series of notable firsts. The first winter ascent was made on 12 February 1985 by the Polish climbers Maciej Berbeka and Maciej Pawlikowski, via a new southeast-face route and without supplemental oxygen. The first women to reach the summit, Věra Komárková of the United States and Dina Štěrbová of Czechoslovakia, did so in 1984, and Marianne Chapuisat made the first female winter ascent in February 1993. Carlos Carsolio set a notable speed record on 13 May 1994, climbing from base camp to summit in 18 hours and 45 minutes.

The overwhelmingly standard line is the northwest ridge, climbed from the Tibetan side. It is a snow, ice and glacier route that deliberately avoids the major serac barriers, vertical rock and sustained technical climbing found on harder eight-thousanders, which is the chief reason Cho Oyu is so often described as the 'easiest' of the fourteen 8,000-metre peaks and is widely chosen as a first eight-thousander.

'Easiest' is relative, however, and real hazards remain. The principal technical obstacle on the normal route is an icefall and serac zone at roughly 6,600 metres, where a barrier of seracs must be passed using fixed ropes. Crevasses, avalanche slopes and the universal dangers of extreme altitude — hypoxia, cold, exhaustion and rapidly changing weather above 8,000 metres — all apply. A further peculiarity is the broad, flat summit plateau: the true high point can be hard to identify, and climbers may have to walk for some minutes across the plateau to be sure they have reached the genuine summit rather than stopping short at prayer flags lower down.

The Tibetan approach offers a practical safety advantage as well: with a road reaching near base camp, an injured or sick climber can often be evacuated to lower altitude far more quickly than from the remote glacier approaches of many other Himalayan giants.

Cho Oyu is generally regarded as the safest of the eight-thousanders, with the lowest death-to-summit ratio of any 8,000-metre peak, commonly estimated at around 1.2 to 1.5 percent — a small fraction of the rate on Annapurna, the most dangerous. The first deaths on the mountain came in the 1950s, including members of a women's expedition killed in an avalanche in 1959; later well-known fatalities include the American Clifton Maloney, who died at 71 shortly after summiting in September 2009.

After Everest, Cho Oyu is the most frequently climbed eight-thousander. Its combination of accessibility, a comparatively forgiving normal route and the genuine prestige of an 8,000-metre summit has made it a common 'first 8,000er' for aspiring high-altitude mountaineers and a staple of commercial Himalayan expeditions.

The mountain is also tied to one of the most documented human-rights incidents in modern Himalayan climbing. On 30 September 2006, Chinese People's Armed Police border guards opened fire on a group of Tibetans attempting to cross the nearby Nangpa La to flee into Nepal and India, killing a 17-year-old nun, Kelsang Namtso. The shooting occurred in view of foreign climbers at Cho Oyu's advance base camp, and footage filmed by Romanian cameraman Sergiu Matei brought the event to international attention, prompting widespread condemnation.