Climbing routes
Southern and northern climbing routes as seen from the International
Space Station.
Mt. Everest has two main climbing routes, the southeast ridge from Nepal and
the northeast ridge from Tibet, as well as many other less frequently climbed
routes. Of the two main routes, the southeast ridge is technically easier and
is the more frequently-used route. It was the route used by Edmund Hillary and
Tenzing Norgay in 1953 and the first recognised of fifteen routes to the top
by 1996. This was, however, a route decision dictated more by politics than
by design as the Chinese border was closed to western world in 1950s after the
Communist China took over the control Tibet from the Republic of China.
Most attempts are made during May before the summer monsoon season. As the monsoon
season approaches, a change in the jet stream at this time pushes it northward,
thereby reducing the average wind speeds high on the mountain. While attempts
are sometimes made after the monsoons in September and October when the jet
stream is again temporarily pushed northward, the additional snow deposited
by the monsoons and the less stable weather patterns (tail end of the monsoon)
makes climbing more difficult.
Southeast ridge
The ascent via the southeast ridge begins with a trek to Base Camp at 5,380 m (17,700 ft) on the south side of Everest in Nepal. Expeditions usually fly into Lukla (2,860 m) from Kathmandu and pass through Namche Bazaar. Climbers then hike to Base Camp, which usually takes six to eight days, allowing for proper altitude acclimatization in order to prevent altitude sickness. Climbing equipment and supplies are carried by yaks, dzopkyos (yak hybrids) and human porters to Base Camp on the Khumbu Glacier. When Hillary and Tenzing climbed Everest in 1953, they started from Kathmandu Valley, as there were no roads further east at that time.
Climbers will spend a couple of weeks in Base Camp, acclimatizing to the altitude. During that time, Sherpas and some expedition climbers will set up ropes and ladders in the treacherous Khumbu Icefall. Seracs, crevasses and shifting blocks of ice make the icefall one of the most dangerous sections of the route. Many climbers and Sherpas have been killed in this section. To reduce the hazard, climbers will usually begin their ascent well before dawn when the freezing temperatures glue ice blocks in place. Above the icefall is Camp I at 6,065 metres (19,900 ft).
From Camp I, climbers make their way up the Western Cwm to the base of the Lhotse face, where Camp II or Advanced Base Camp (ABC) is established at 6,500 m (21,300 ft). The Western Cwm is a relatively flat, gently rising glacial valley, marked by huge lateral crevasses in the centre which prevent direct access to the upper reaches of the Cwm. Climbers are forced to cross on the far right near the base of Nuptse to a small passageway known as the "Nuptse corner". The Western Cwm is also called the "Valley of Silence" as the topography of the area generally cuts off wind from the climbing route. The high altitude and a clear, windless day can make the Western Cwm unbearably hot for climbers.
From ABC, climbers ascend the Lhotse face on fixed ropes up to Camp III, located on a small ledge at 7,470 m (24,500 ft). From there, it is another 500 metres to Camp IV on the South Col at 7,920 m (26,000 ft). From Camp III to Camp IV, climbers are faced with two additional challenges: The Geneva Spur and The Yellow Band. The Geneva Spur is an anvil shaped rib of black rock named by a 1952 Swiss expedition. Fixed ropes assist climbers in scrambling over this snow covered rock band. The Yellow Band is a section of interlayered marble, phyllite, and semischist which also requires about 100 metres of rope for traversing it.
On the South Col, climbers enter the death zone. Climbers typically only have a maximum of two or three days they can endure at this altitude for making summit bids. Clear weather and low winds are critical factors in deciding whether to make a summit attempt. If weather does not cooperate within these short few days, climbers are forced to descend, many all the way back down to Base Camp.
From Camp IV, climbers will begin their summit push around midnight with hopes of reaching the summit (still another 1,000 metres above) within 10 to 12 hours. Climbers will first reach "The Balcony" at 8,400 m (27,600 ft), a small platform where they can rest and gaze at peaks to the south and east in the early dawn light. Continuing up the ridge, climbers are then faced with a series of imposing rock steps which usually forces them to the east into waist deep snow, a serious avalanche hazard. At 8,750 m (28,700 ft), a small table-sized dome of ice and snow marks the South Summit.
From the South Summit, climbers follow the knife-edge southeast ridge along what is known as the "Cornice traverse" where snow clings to intermittent rock. This is the most exposed section of the climb as a misstep to the left would send one 2,400 m (8,000 ft) down the southwest face while to the immediate right is the 3,050 m (10,000 ft) Kangshung face. At the end of this traverse is an imposing 12 m (40 ft) rock wall called the "Hillary Step" at 8,760 m (28,740 ft).
Hillary and Tenzing were the first climbers to ascend this step and they did it with primitive ice climbing equipment and without fixed ropes. Nowadays, climbers will ascend this step using fixed ropes previously set up by Sherpas. Once above the step, it is a comparatively easy climb to the top on moderately angled snow slopes - though the exposure on the ridge is extreme especially while traversing very large cornices of snow. With increasing numbers of people climbing the mountain in recent years, the Step has frequently become a bottleneck, with climbers forced to wait significant amounts of time for their turn on the ropes, leading to problems in getting climbers efficiently up and down the mountain. After the Hillary Step, climbers also must traverse a very loose and rocky section that has a very large entanglement of fixed ropes that can be troublesome in bad weather. Climbers will typically spend less than a half-hour on "top of the world" as they realize the need to descend to Camp IV before darkness sets in, afternoon weather becomes a serious problem, or supplemental oxygen tanks run out.
Northeast ridge
Everest North Face, Tibet
The northeast ridge route begins from the north side of Everest in Tibet. Expeditions
trek to the Rongbuk Glacier, setting up Base Camp at 5,180 m (16,990 ft) on
a gravel plain just below the glacier. To reach Camp II, climbers ascend the
medial moraine of the east Rongbuk Glacier up to the base of Changtse at around
6,100 m (20,000 ft). Camp III (ABC - Advanced Base Camp) is situated below the
North Col at 6,500 m (21,300 ft). To reach Camp IV on the north col, climbers
ascend the glacier to the foot of the col where fixed ropes are used to reach
the North Col at 7,010 m (23,000 ft). From the North Col, climbers ascend the
rocky north ridge to set up Camp V at around 7,775 m (25,500 ft). The route
goes up the north face through a series of gullies and steepens into downsloping
slabby terrain before reaching the site of Camp VI at 8,230 m (27,000 ft). From
Camp VI, climbers will make their final summit push. Climbers must first make
their way through three rock bands known as First Step: 27,890 feet - 28,000
feet, Second Step: 28,140 feet - 28,300 feet, and Third Step: 28,510 feet -
28,870 feet. (The Second Step includes a climbing aid called the "Chinese
ladder", a metal ladder placed semi-permanently in 1975 by a party of Chinese
climbers. It has been almost continuously in place since, and is used by virtually
all climbers on the route.) Once above these steps, the final summit slopes
(50 to 60 degrees) to the top.
China is paving a 130 km (81 mi) dirt road from Tingri County to its Base Camp in order to accommodate growing numbers of climbers on their side of the mountain. It will become the highest asphalt-paved road in the world. Construction began on June 18, 2007, at a cost of 150 million yuan (US$19.7 million). China also routed the 2008 Olympic Torch Relay over Everest, going up the South Col route and back down the North Col route, on the way to the 2008 Summer Olympics in Beijing.