See S. B. Ortner, Life and Death on Mt. Everest (1999).
Peak on the crest of the Himalayas, southern Asia. The highest point on Earth, with a summit at 29,035 ft (8,850 m), it lies on the border between Nepal and the Tibet Autonomous Region of China. Numerous attempts to climb Everest were made from 1921; the summit was finally reached by Edmund Hillary of New Zealand and Tenzing Norgay of Nepal in 1953. In dispute is whether the English explorer George Mallory, whose body was discovered below Everest's peak in 1999, had actually reached the peak earlier, in 1924, and was descending it when he died. The formerly accepted elevation of 29,028 ft (8,848 m), established in the early 1950s, was recalculated in the late 1990s.
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Mount Everest, also called Sagarmatha (सगरमाथा meaning Head of the Sky) or Chomolungma, Qomolangma or Zhumulangma (in ཇོ་མོ་གླང་མ, in Chinese: 珠穆朗玛峰 Zhūmùlǎngmǎ Fēng) is the highest mountain on Earth, as measured by the height of its summit above sea level, which is . The mountain, which is part of the Himalaya range in High Asia, is located on the border between Sagarmatha Zone, Nepal, and Tibet, China.
In 1856, the Great Trigonometric Survey of India established the first published height of Everest at , although at the time Everest was known as Peak XV. In 1865, Everest was given its official English name by the Royal Geographical Society upon recommendation of Andrew Waugh, the British Surveyors General of India at the time. Waugh was unable to propose an established local name due to Nepal and Tibet being closed to foreigners at the time, although Chomolungma had been in common use by Tibetans for centuries.
The highest mountain in the world attracts climbers of all levels, from well experienced mountaineers to novice climbers willing to pay substantial sums to professional mountain guides to complete a successful climb. The mountain, while not posing substantial technical climbing difficulty on the standard route (other eight-thousanders such as K2 or Nanga Parbat are much more difficult), still has many inherent dangers such as altitude sickness, weather and wind. By the end of the 2007 climbing season, there had been 3,679 ascents to the summit by 2,436 individuals. This means climbers are a significant source of tourist revenue for Nepal, whose government also requires all prospective climbers to obtain an expensive permit, costing up to US$25,000 per person. Everest has claimed 210 lives, including eight who perished during a 1996 storm high on the mountain. Conditions are so difficult in the death zone that most corpses have been left where they fell, some of which are visible from standard climbing routes.
In 1808, the British began the Great Trigonometric Survey of India to determine the location and names of the world's highest mountains. Starting in southern India, the survey teams gradually moved northward using giant 1100 pound (500 kg) theodolites (each requiring 12 men to carry) to measure heights as accurately as possible. They reached the Himalayan foothills by the 1830s, but Nepal was unwilling to allow the British to enter the country due to suspicions of political aggression and possible annexation. Several requests by the surveyors to enter Nepal were turned down.
The British were forced to continue their observations from Terai, a region south of Nepal which is parallel to the Himalayas. Conditions in Terai were difficult due to torrential rains and malaria — three survey officers died from malaria while two others had to retire due to failing health.
Nonetheless, in 1847, the British pressed on and began detailed observations of the Himalayan peaks from observation stations up to away. Weather restricted work to the last three months of the year. In November 1847, Andrew Waugh, the British Surveyors General of India made a number of observations from Sawajpore station located in the eastern end of the Himalayas. At the time, Kangchenjunga was considered the highest peak in the world, and with interest he noted a peak beyond it, some away. John Armstrong, one of Waugh's officials, also saw the peak from a location further west and called it peak 'b'. Waugh would later write that the observations indicated that peak 'b' was higher than Kangchenjunga, but due to the great distance of the observations, closer observations were required for verification. The following year, Waugh sent a survey official back to Terai to make closer observations of peak 'b', but clouds thwarted all attempts.
In 1849, Waugh dispatched James Nicolson to the area. Nicolson was able to make two observations from Jirol, away. Nicolson then took the largest theodolite and headed east, obtaining over 30 observations from five different locations, with the closest being away from the peak.
Nicolson retreated to Patna on the Ganges to perform the necessary calculations based on his observations. His raw data gave an average height of for peak 'b', but this did not take into account light refraction which distorts heights. The number clearly indicated, however, that peak 'b' was higher than Kangchenjunga. Unfortunately, Nicolson came down with malaria and was forced to return home, calculations unfinished. Michael Hennessy, one of Waugh's assistants, had begun designating peaks based on Roman Numerals, with Kangchenjunga named Peak IX, while peak 'b' now became known as Peak XV.
In 1852, stationed at the survey's headquarters in Dehradun, Radhanath Sikdar, an Indian mathematician and surveyor from Bengal, was the first to identify Everest as the world's highest peak, using trigonometric calculations based on Nicolson's measurements. An official announcement that Peak XV was the highest was delayed for several years as the calculations were repeatedly verified. Waugh began work on Nicolson's data in 1854, and along with his staff spent almost two years working on the calculations, having to deal with the problems of light refraction, barometric pressure, and temperature over the vast distances of the observations. Finally, in March 1856 he announced his findings in a letter to his deputy in Calcutta. Kangchenjunga was declared to be , while Peak XV was given the height of . Waugh concluded that Peak XV was "most probably the highest in the world". Peak XV was found to be exactly high, but was publicly declared to be . The arbitrary addition of 2 feet (60 cm) was to avoid the impression that an exact height of 29,000 feet was nothing more than a rounded estimate.
With the height now established, what to name the peak was clearly the next challenge. While the survey was anxious to preserve local names if possible (e.g., Kangchenjunga and Dhaulagiri were local names), Waugh argued that he was unable to find any commonly used local name. Waugh's search for a local name was hampered by Nepal and Tibet being closed to foreigners at the time. Many local names existed, with perhaps the best known in Tibet for several centuries being Chomolungma, which had appeared on a 1733 map published in Paris by the French geographer D'Anville. However, Waugh argued that with the plethora of local names, it would be difficult to favour one specific name over all others. So, he decided that Peak XV should be named after George Everest, his predecessor as Surveyor General of India. He wrote:
I was taught by my respected chief and predecessor, Colonel Sir George Everest to assign to every geographical object its true local or native appellation. But here is a mountain, most probably the highest in the world, without any local name that we can discover, whose native appellation, if it has any, will not very likely be ascertained before we are allowed to penetrate into Nepal. In the meantime the privilege as well as the duty devolves on me to assign…a name whereby it may be known among citizens and geographers and become a household word among civilized nations.
George Everest opposed the name suggested by Waugh and told the Royal Geographical Society in 1857 that Everest could not be written in Hindi nor pronounced by "the native of India". Waugh's proposed name prevailed despite the objections, and in 1865, the Royal Geographical Society officially adopted Mount Everest as the name for the highest mountain in the world.
The Tibetan name for Mount Everest is Chomolungma or Qomolangma (ཇོ་མོ་གླིང་མ, which means "Saint Mother"), and the Chinese transliteration is Zhūmùlǎngmǎ Fēng which refers to Earth Mother; the Chinese translation is Shèngmǔ Fēng which refers to Holy Mother. According to English accounts of the mid-19th century, the local name in Darjeeling for Mount Everest was Deodungha, or "Holy Mountain".
In 1865, the mountain was officially given its English name by the Royal Geographical Society after being proposed by Andrew Waugh, the British Surveyors General of India. Waugh chose to name the mountain after George Everest, first using the spelling Mont Everest, and then Mount Everest. However, the modern pronunciation of Everest is in fact different from Sir George's own pronunciation of his surname, which was /ˈiːvrɪst/.
In the late 19th century, many European cartographers incorrectly believed that a native name for the mountain was "Gaurisankar". This was a result of confusion of Mount Everest with the actual Gauri Sankar, which, when viewed from Kathmandu, stands almost directly in front of Everest.
In the early 1960s, the Nepalese government gave Mount Everest the official name Sagarmatha (सगरमाथा). This name had not previously been used; the local inhabitants knew the mountain as Chomolungma. The mountain was not known and named in ethnic Nepal (that is, the Kathmandu valley and surrounding areas). The government set out to find a Nepalese name for the mountain because the Sherpa/Tibetan name Chomolangma was not acceptable, as it would have been against the idea of unification (Nepalization) of the country.
In 2002, the Chinese People's Daily newspaper published an article making a case against the continued use of the English name for the mountain in the Western world, insisting that it should be referred to by its Tibetan name. The newspaper argued that the Chinese (in nature a Tibetan) name preceded the English one, as Mount Qomolangma was marked on a Chinese map more than 280 years ago.
In 1856, Andrew Waugh announced Everest (then known as Peak XV) as high, after several years of calculations based on observations made by the Great Trigonometric Survey.
More recently, the mountain has been found to be high, although there is some variation in the measurements. On 9 October 2005, after several months of measurement and calculation, the PRC's State Bureau of Surveying and Mapping officially announced the height of Everest as 8,844.43 m ± 0.21 m (29,017.16 ± 0.69 ft). They claimed it was the most accurate and precise measurement to date. This height is based on the actual highest point of rock and not on the snow and ice covering it. The Chinese team also measured a snow/ice depth of 3.5 m, which is in agreement with a net elevation of 8,848 m. The snow and ice thickness varies over time, making a definitive height of the snow cap impossible to determine.
The elevation of was first determined by an Indian survey in 1955, made closer to the mountain, also using theodolites. It was subsequently reaffirmed by a 1975 Chinese measurement. In both cases the snow cap, not the rock head, was measured. In May 1999 an American Everest Expedition, directed by Bradford Washburn, anchored a GPS unit into the highest bedrock. A rock head elevation of 8,850 m (29,035 ft), and a snow/ice elevation 1 m (3 ft) higher, were obtained via this device. Although it has not been officially recognized by Nepal, this figure is widely quoted. Geoid uncertainty casts doubt upon the accuracy claimed by both the 1999 and 2005 surveys.
A detailed photogrammetric map (at a scale of 1:50,000) of the Khumbu region, including the south side of Mount Everest, was made by Erwin Schneider as part of the 1955 International Himalayan Expedition, which also attempted Lhotse. An even more detailed topographic map of the Everest area was made in the late 1980s under the direction of Bradford Washburn, using extensive aerial photography.
It is thought that the plate tectonics of the area are adding to the height and moving the summit north-eastwards. Two accounts suggest the rates of change are per year (upwards) and 3-6 mm (0.12-0.25 in) per year (northeastwards), but another account mentions more lateral movement (), and even shrinkage has been suggested.
By the same measure of base to summit, Mount McKinley, in Alaska, is also taller than Everest. Despite its height above sea level of only , Mount McKinley sits atop a sloping plain with elevations from 300-900 m (1,000-3,000 ft), yielding a height above base in the range of 5,300-5,900 m (17,300-19,300 ft); a commonly quoted figure is . By comparison, reasonable base elevations for Everest range from on the south side to on the Tibetan Plateau, yielding a height above base in the range of 3,650 m (12,000 ft) to 4,650 m (15,300 ft).
The summit of Chimborazo in Ecuador is farther from the Earth's centre (6,384.4 km or 3,967.1 mi) than that of Everest (6,382.3 km or 3,965.8 mi), because the Earth bulges at the Equator. However, Chimborazo attains a height of only above sea level, and by this criterion it is not even the highest peak of the Andes.
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 the 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.
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 .
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 . 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 . From there, it is another 500 metres to Camp IV on the South Col at . 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 , 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 , 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 .
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.
The northeast ridge route begins from the north side of Everest in Tibet. Expeditions trek to the Rongbuk Glacier, setting up Base Camp at 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 . 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 . From the North Col, climbers ascend the rocky north ridge to set up Camp V at around . The route crosses the North Face in a diagonal climb to the base of the Yellow Band reaching the site of Camp VI at . From Camp VI, climbers will make their final summit push. Climbers face a treacherous traverse from the base of the First Step: 27,890 feet - 28,000 feet, to the crux of the climb, the Second Step: 28,140 feet - 28,300 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 the Second Step the inconsequential Third Step is clambered over: 28,510 feet - 28,870 feet. Once above these steps, the summit pyramid is climbed by means of a snow slope of 50 degrees, to the final summit ridge along which the top is reached.
The northern approach to the mountain was discovered by George Mallory on the first expedition in 1921. It was an exploratory expedition not equipped for a serious attempt to climb the mountain. With Mallory leading (and thus becoming the first European to set foot on Everest's flanks) they climbed the North Col . From there, Mallory espied a route to the top, but the party was woefully unprepared for the enormity of climbing any further and descended.
The British returned in 1922. George Finch ("The other George") climbed using oxygen for the first time. He ascended at a remarkable speed — per hour, a feat that was entirely lost on the British climbing establishment — except for its unsporting nature. Mallory and Col. Felix Norton made a second unsuccessful attempt. Mallory was faulted for leading a group down from the North Col which got caught in an avalanche. Mallory was pulled down too, but seven native porters were killed.
The next Expedition was in 1924. The initial attempt by Mallory and Bruce, was aborted when weather conditions precluded the establishment of Camp VI. The next attempt was that of Norton and Somervell who climbed without oxygen and in perfect weather, traversing the North Face into the Great Couloir. Norton managed to reach , though he ascended only or so in the last hour. Mallory rustled-up oxygen equipment for a last-ditch effort. He choose the young Andrew Irvine as his partner.
On 8 June 1924, George Mallory and Andrew Irvine, made an attempt on the summit via the North Col/North Ridge/Northeast Ridge route from which they never returned. On 1999-05-01, the Mallory and Irvine Research Expedition found Mallory's body on the North Face in a snow basin below and to the west of the traditional site of Camp VI. Controversy has raged in the mountaineering community as to whether or not one or both of them reached the summit 29 years before the confirmed ascent (and of course, safe descent) of Everest by Sir Edmund Hillary and Tenzing Norgay in 1953. The general consensus among climbers has been that they did not.
In 1933, Lady Houston, a British millionaire ex-showgirl, funded the Houston Everest Flight of 1933, which saw a formation of aircraft led by the Marquess of Clydesdale fly over the summit in an effort to deploy the British Union Flag at the top.
Early expeditions — such as Bruce's in the 1920s and Hugh Ruttledge's two unsuccessful attempts in 1933 and 1936 — tried to make an ascent of the mountain from Tibet, via the north face. Access was closed from the north to western expeditions in 1950, after the Chinese asserted control over Tibet. In 1950, Bill Tilman and a small party which included Charles Houston, Oscar Houston and Betsy Cowles undertook an exploratory expedition to Everest through Nepal along the route which has now become the standard approach to Everest from the south.
In the spring of 1952 a Swiss expedition, lead by Edouard Wyss-Dunant was granted permission to attempt a climb from Nepal. The expedition established a route through the Khumbu ice fall and ascended to the South Col at an elevation of . Raymond Lambert and Sherpa Tenzing Norgay were able to reach a height of about on the south-east ridge, setting a new climbing altitude record. Tenzing's experience was useful when he was hired to be part of the British expedition in 1953.
News of the expedition's success reached London on the morning of Queen Elizabeth II's coronation. Returning to Kathmandu a few days later, Hunt (a Briton) and Hillary (a subject of Elizabeth, through her role as head of state of New Zealand) discovered that they had been promptly knighted in the Order of the British Empire, a KBE, for the ascent. Tenzing (a subject of the King of Nepal) was granted the George Medal by the UK. Hunt was ultimately made a life peer in Britain, while Hillary became a founding member of the Order of New Zealand.
During the 1996 climbing season, fifteen people died trying to come down from the summit, making it the deadliest single year in Everest history. Eight of them died on 11 May alone. The disaster gained wide publicity and raised questions about the commercialization of Everest.
Journalist Jon Krakauer, on assignment from Outside magazine, was in one of the affected parties, and afterwards published the bestseller Into Thin Air which related his experience. Anatoli Boukreev, a guide who felt impugned by Krakauer's book, co-authored a rebuttal book called The Climb. The dispute sparked a large debate within the climbing community. In May 2004, Kent Moore, a physicist, and John L. Semple, a surgeon, both researchers from the University of Toronto, told New Scientist magazine that an analysis of weather conditions on 11 May suggested that freak weather caused oxygen levels to plunge approximately 14%.
The storm's impact on climbers on the mountain's other side, the North Ridge, where several climbers also died, was detailed in a first hand account by British filmmaker and writer Matt Dickinson in his book The Other Side of Everest.
Delsalle had also performed, two days earlier, a take-off from the South Col; some press reports suggested that the report of the summit landing was a misunderstanding of a South Col one.
Double-amputee climber Mark Inglis revealed in an interview with the press on 23 May 2006, that his climbing party, and many others, had passed a distressed climber, David Sharp, on 15 May, sheltering under a rock overhang 450 metres below the summit, without attempting a rescue. The revelation sparked wide debate on climbing ethics, especially as applied to Everest. The climbers who left him said that the rescue efforts would be useless and only cause more deaths because of how many people it would have taken to pull him off.
Much of this controversy was captured by the Discovery Channel while filming the television program Everest: Beyond the Limit. A crucial decision affecting the fate of Sharp is shown in the program, where an early returning climber (Max Chaya) is descending and radios to his base camp manager (Russell Brice) that he has found a climber in distress. He is unable to identify Sharp, and Sharp had chosen to climb solo without any support, so he did not identify himself to other climbers. The base camp manager assumes that Sharp is part of a group that has abandoned him, and informs his climber that there is no chance of him being able to help Sharp [at 8000+ meters in altitude, barely anyone has the strength to help another man who is only semi conscious, and Max Chaya is only an amateur mountaineer]. As Sharp's condition deteriorates through the day and other descending climbers pass him, his opportunities for rescue diminish: his legs and feet curl from frost-bite, preventing him from walking; the later descending climbers are lower on oxygen and lack the strength to offer aid; time runs out for any Sherpas to return and rescue him. Most importantly, Sharp's decision to forgo all support leaves him with no margin for recovery.
As this debate raged, on 26 May, Australian climber Lincoln Hall was found alive, after being declared dead the day before. He was found by a party of four climbers (Dan Mazur, Andrew Brash, Myles Osborne and Jangbu Sherpa) who, giving up their own summit attempt, stayed with Hall and descended with him and a party of 11 Sherpas sent up to carry him down. Hall later fully recovered. Similar actions have been recorded since, including on 21 May 2007, when Canadian climber Meagan McGrath initiated the successful high-altitude rescue of Nepali Usha Bista.
The fastest ascent over the northeast ridge was accomplished in 2007 by Austrian climber Christian Stangl, who needed 16h 42min for the 10km distance from Camp III to the summit, just barely beating Italian Hans Kammerlander's record of 17 hours, accomplished in 1996. Both men climbed alone and without supplementary oxygen. The fastest oxygen-supported ascent over the southeast ridge was Nepalese Pemba Dorjie Sherpa's 2004 climb, using 8h 10min for the 17km route. The fastest ascent without supplementary oxygen over the southeast ridge was accomplished by French Marc Batard who needed 22h 30min in 1988.
The oldest climber to successfully reach Mt. Everest's summit was 76-year-old Min Bahadur Sherchan, who did so 25 May 2008.
As part of Everest Skydive 2008, an event of twenty-nine skydivers, three internationally known parachutists became the first to skydive above Everest. Neil Jone, Holly Budge and Wendy Smith were flown to 29,500 feet, 2,500 feet above Everest. From there, they jumped in their thermal suit, oxygen tank and extra-thick parachutes landing back at Shyangboche airport 12,350 feet below.
Even at base camp the low level of available oxygen had direct effect on blood oxygen saturation levels. At sea level these are usually 98% to 99%, but at base camp this fell to between 85% and 87%. Blood samples taken at the summit indicated very low levels of oxygen present. A side effect of this is a vastly increased breathing rate, from 20-30 breaths per minute to 80-90 breaths, leading to exhaustion just trying to breathe.
Lack of oxygen, exhaustion, extreme cold, and the dangers of the climb all contribute to the death toll.
People who die during the climb are typically left behind. About 150 bodies have never been recovered. It is not uncommon that corpses are visible from the standard climbing routes.
One sometimes deadly phenomenon, however, does not plague climbers — lightning. Lightning does not strike Mount Everest. NASA's lightning detection system does record significant lightning in the Tibet plateau, but none along the high Tibetan mountains, from about 2000 m (7,000 feet) and above.
Most expeditions use oxygen masks and tanks above 8,000 m (26,246 ft). Everest can be climbed without supplementary oxygen but this increases the risk to the climber. Humans do not think clearly with low oxygen, and the combination of severe weather, low temperatures, and steep slopes often require quick, accurate decisions.
The use of bottled oxygen to ascend Mount Everest has been controversial. George Mallory himself described the use of such oxygen as unsportsmanlike, but he later concluded that it would be impossible to summit without it and consequently used it. When Tenzing and Hillary made the first successful summit in 1953, they used bottled oxygen. For the next twenty-five years, bottled oxygen was considered standard for any successful summit.
Reinhold Messner was the first climber to break the bottled oxygen tradition and in 1978, with Peter Habeler, made the first successful climb without it. Although critics alleged that he sucked mini-bottles of oxygen - a claim that Messner denied - Messner silenced them when he summited the mountain solo, without supplemental oxygen or any porters or climbing partners, on the more difficult northwest route, in 1980.
The aftermath of the 1996 disaster further intensified the debate. Jon Krakauer's Into Thin Air (1997) expressed the author's personal criticisms of the use of bottled oxygen. Krakauer wrote that the use of bottled oxygen allowed otherwise unqualified climbers to attempt to summit, leading to dangerous situations and more deaths. The 11 May 1996 disaster was partially caused by the sheer number of climbers (34 on that day) attempting to ascend, causing bottlenecks at the Hillary Step and delaying many climbers, most of whom summited after the usual 2 p.m. turnaround time. He proposed banning bottled oxygen except for emergency cases, arguing that this would both decrease the growing pollution on Everest—many bottles have accumulated on its slopes—and keep marginally qualified climbers off the mountain.
The 1996 disaster also introduced the issue of the guide's role in using bottled oxygen. Guide Anatoli Boukreev's decision not to use bottled oxygen was sharply criticized by Jon Krakauer. Boukreev's supporters (who include G. Weston DeWalt, who co-wrote The Climb) state that using bottled oxygen gives a false sense of security. Krakauer and his supporters point out that, without bottled oxygen, Boukreev was unable to directly help his clients descend. They state that Boukreev said that he was going down with client Martin Adams, but just below the South Summit, Boukreev determines that Adams was doing fine on the descent and so descends at a faster pace, leaving Adams behind. Adams states in The Climb: "For me, it was business as usual, Anatoli's going by, and I had no problems with that."
In addition to theft, the 2008 book High Crimes by Michael Kodas describes unethical guides and sherpas, prostitution and gambling at the Tibet Base Camp, fraud related to the sale of oxygen bottles, and climbers collecting donations under the pretense of removing trash from the mountain.
Euophrys omnisuperstes, a minute black jumping spider, has been found at elevations as high as , possibly making it the highest confirmed permanent resident on Earth. They lurk in crevices and possibly feed on frozen insects that have been blown there by the wind. It should be noted that there is a high likelihood of microscopic life at even higher altitudes. Birds, such as the bar-headed goose, have been seen flying at the higher altitudes of the mountain, while others such as the Chough have been spotted as high as the South Col (7,920 m), scavenging on food, or even corpses, left over by climbing expeditions.
Geologists have subdivided the rocks comprising Mount Everest into three units called "formations". Each of these formations are separated from each other by low-angle faults, called “detachments”, along which they have been thrust over each other. From the summit of Mount Everest to its base these rock units are the Qomolangma Formation, the North Col Formation, and the Rongbuk Formation.
From its summit to the top of the Yellow Band, about 8,600 m above sea level, the top of Mount Everest consists of the Qomolangma Formation, which has also been designated as either the Everest Formation or Jolmo Lungama Formation. It consists of grayish to dark gray or white, parallel laminated and bedded limestone interlayered with subordinate beds of recrystallized dolomite with argillaceous laminae and siltstone. Gansser reported finding visible fragments of crinoids in these limestones. Petrographic analysis of samples of this Ordovician limestone from near the summit revealed them to be composed of carbonate pellets and finely fragmented remains of trilobites, crinoids, and ostracods. Other samples were so badly sheared and recrystallized that their original constituents could not be determined. The Qomolangma Formation is broken up by several high-angle faults that terminate at the low angle thrust fault, the Qomolangma Detachment. This detachment separates it from the underlying Yellow Band. The lower five metres of the Qomolangma Formation overlying this detachment are very highly deformed.
The bulk of Mount Everest, between 7,000 and 8,600 m, consists of the North Col Formation, of which the Yellow Band forms its upper part between 8,200 to 8,600 m. The Yellow Band consists of intercalated beds of diopsite-epidote-bearing marble, which weathers a distinctive yellowish brown, and muscovite-biotite phyllite and semischist. Petrographic analysis of marble collected from about 8,300 m found it to consist as much as five percent of the ghosts of recrystallized crinoid ossicles. The upper five metres of the Yellow Band lying adjacent to the Qomolangma Detachment is badly deformed. A 5–40 cm thick fault breccia separates it from the overlying Qomolangma Formation.
The remainder of the North Col Formation, exposed between 7,000 to 8,200 m on Mount Everest, consists of interlayered and deformed schist, phyllite, and minor marble. Between 7,600 and 8,200 m, the North Col Formation consists chiefly of biotite-quartz phyllite and chlorite-biotite phyllite intercalated with minor amounts of biotite-sericite-quartz schist. Between 7,000 and 7,600 m, the lower part of the North Col Formation consists of biotite-quartz schist intercalated with epidote-quartz schist, biotite-calcite-quartz schist, and thin layers of quartzose marble. These metamorphic rocks appear to the result of the metamorphism of deep sea flysch composed of interbedded, mudstone, shale, clayey sandstone, calcareous sandstone, graywacke, and sandy limestone. The base of the North Col Formation is a regional thrust fault called the “Lhotse detachment”.
Below 7,000 m, the Rongbuk Formation underlies the North Col Formation and forms the base of Mount Everest. It consists of sillminite-K-feldspar grade schist and gneiss intruded by numerous sills and dikes of leucogranite ranging in thickness from one cm to 1,500 m.