Mount Everest (also called Sagarmāthā / Chomolungma or Qomolangma / Zhumulangma / Zhūmùlǎngmǎ Fēng), the highest mountain on Earth (8,848 meters or 29,029 ft), has two main climbing routes, the southeast ridge from Nepal and the northeast ridge from Tibet. The southeast ridge is technically easier and is the more frequently used route. It was the route used by Sir Edmund Hillary (New Zealand mountaineer and explorer) and Tenzing Norgay (aka Sherpa Tenzing, a Nepali Indian Sherpa mountaineer who later settled in India) in 1953 and the first recognized of fifteen routes to the top by 1996.
The ascent via the southeast ridge begins with a trek to Base Camp at 5,380 m (17,700 feet) 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. Climbing equipment and supplies are carried by yaks, dzopkyos (yak hybrids) and human porters to Base Camp on the Khumbu Glacier. When Edmund Hillary and Tenzing Norgay climbed Everest in 1953, they started from Kathmandu Valley, as there were no roads further east at that time.
Climbers spend a couple of weeks in Base Camp, acclimatizing to the altitude in order to prevent altitude sickness. During that time, Sherpas (Sherpas are an ethnic group, who migrated from eastern Tibet to Nepal within the last 300 to 400 years) from the most mountainous region of Nepal, high in the Himalayas) 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 meters (19,900 ft).
From Camp I, climbers make their way up the Western Cwm (Cwm, pronounced as coom, is Welsh for a bowl shaped valley/cirque) 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 meters 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 inter-layered marble, phyllite, and semischist which also requires about 100 meters 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 meters 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 of 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, there is an imposing 12 m (40 ft) rock wall called the "Hillary Step" at 8,760 m (28,740 ft).
Edmund Hillary and Tenzing Norgay were the first climbers to ascend this step and they did it with primitive ice climbing equipment and with 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 the "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.
Mount Everest, which is part of the Himalaya range in Asia, is located on the border between Sagarmatha Zone, Nepal, and Tibet, China.
Adapted from: Wikipedia