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Mount Everest From Wikipedia, the free encyclopedia (Redirected from Mt everest) "Everest" redirects here. For other uses, see Everest (disambiguation). Page semi-protected Mount Everest सगरमाथा (Sagarmāthā) ཇོ་མོ་གླང་མ (Chomolungma) 珠穆朗玛峰 (Zhūmùlǎngmǎ Fēng) Sunny Everest.JPG Morning view of Mount Everest from its southern side Elevation	8,848 m (29,029 ft)[1] Ranked 1st Prominence	8,848 m (29,029 ft) Ranked 1st (Notice special definition for Everest) Listing	Seven Summits Eight-thousander Country high point Ultra Location Mount Everest is located in Nepal Mount EverestMount Everest Location on the Sagarmatha Zone, Nepal - Tibet, China border Location	Solukhumbu District, Sagarmatha Zone, Nepal; Tingri County, Xigazê, Tibet Autonomous Region, China[2] Range	Mahalangur Himal, Himalayas Coordinates	27°59′17″N 86°55′31″ECoordinates: 27°59′17″N 86°55′31″E[3] Climbing First ascent	29 May 1953 Edmund Hillary and Tenzing Norgay (First Winter Ascent 1980 Leszek Cichy and Krzysztof Wielicki[4][5]) Easiest route	South Col (Nepal)

Everest from space Mount Everest, also known in Nepal as Sagarmāthā and in Tibet as Chomolungma, is Earth's highest mountain. It is located in the Mahalangur section of the Himalayas. Its peak is 8,848 metres (29,029 ft) above sea level[1] and is the 5th furthest summit from the center of Earth.[6] The international border between China and Nepal runs across the precise summit point. Its massif includes neighboring peaks Lhotse, 8,516 m (27,940 ft); Nuptse, 7,855 m (25,771 ft) and Changtse, 7,580 m (24,870 ft).

In 1856, the Great Trigonometrical Survey of India established the first published height of Everest, then known as Peak XV, at 29,002 ft (8,840 m). The current official height of 8,848 m (29,029 ft) as recognized by Nepal and China was established by a 1955 Indian survey and subsequently confirmed by a Chinese survey in 1975. In 1865, Everest was given its official English name by the Royal Geographical Society upon a recommendation by Andrew Waugh, the British Surveyor General of India. Waugh named the mountain after his predecessor in the post, Sir George Everest, arguing that there were many local names, against the opinion of Everest.[7]

Mount Everest attracts many highly experienced mountaineers as well as capable climbers willing to hire professional guides. There are two main climbing routes, one approaching the summit from the southeast in Nepal (known as the standard route) and the other from the north in Tibet. While not posing substantial technical climbing challenges on the standard route, Everest presents dangers such as altitude sickness, weather, wind as well as significant objective hazards from avalanches and the Khumbu Icefall. While the overwhelming majority of climbers use bottled oxygen in order to reach the top, some climbers have summitted Everest without supplemental oxygen.

The first recorded efforts to reach Everest's summit were made by British mountaineers. With Nepal not allowing foreigners into the country at the time, the British made several attempts on the north ridge route from the Tibetan side. After the first reconnaissance expedition by the British in 1921 reached 7,000 m (22,970 ft) on the North Col, the 1922 expedition pushed the North ridge route up to 8,320 m (27,300 ft) marking the first time a human had climbed above 8,000 m (26,247 ft). Tragedy struck on the descent from the North col when seven porters were killed in an avalanche. The 1924 expedition resulted in the greatest mystery on Everest to this day: George Mallory and Andrew Irvine made a final summit attempt on June 8 but never returned, sparking debate as to whether they were the first to reach the top. They had been spotted high on the mountain that day but disappeared in the clouds, never to be seen again until Mallory's body was found in 1999 at 8,155 m (26,755 ft) on the North face. Tenzing Norgay and Edmund Hillary made the first official ascent of Everest in 1953 using the southeast ridge route. Tenzing had reached 8,595 m (28,199 ft) the previous year as a member of the 1952 Swiss expedition.

Contents [hide] 1 Discovery 2 Name 3 Surveys 3.1 Comparisons 4 Geology 5 Flora and fauna 6 Environment 7 History of expeditions 7.1 Early attempts 7.2 First successful ascent by Tenzing and Hillary 7.3 Routes 7.3.1 Southeast ridge 7.3.2 North ridge route 7.4 Death zone 7.5 Supplemental oxygen 7.6 Selected climbing records 7.7 1996 disaster 7.8 2005: Helicopter landing 7.9 2006: Controversy 7.10 Ascent statistics to 2010 7.11 2014 avalanche 7.12 Shut downs 7.13 Everest economy 7.14 Climbing crimes 8 Everest and religion 9 Map 10 See also 11 References 12 Further reading 13 External links Discovery Mount Everest is located in Tibet. Mount Everest is located in Tibet. Location on Earth

Mount Everest relief map In 1802, 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 moved northward using giant theodolites, each weighing 500 kg (1,100 lb) and 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 because of suspicions of political aggression and possible annexation. Several requests by the surveyors to enter Nepal were turned down.[8]

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 because of torrential rains and malaria. Three survey officers died from malaria while two others had to retire due to failing health.[8]

Nonetheless, in 1847, the British continued the Great Trigonometric survey and began detailed observations of the Himalayan peaks from observation stations up to 240 km (150 mi) away. Weather restricted work to the last three months of the year. In November 1847, Andrew Waugh, the British Surveyor General of India made several observations from the Sawajpore station located in the eastern end of the Himalayas. Kangchenjunga was then considered the highest peak in the world, and with interest he noted a peak beyond it, about 230 km (140 mi) away. John Armstrong, one of Waugh's officials, also saw the peak from a location farther west and called it peak "b". Waugh would later write that the observations indicated that peak "b" was higher than Kangchenjunga, but given 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.[8]

In 1849, Waugh dispatched James Nicolson to the area, who made two observations from Jirol, 190 km (120 mi) away. Nicolson then took the largest theodolite and headed east, obtaining over 30 observations from five different locations, with the closest being 174 km (108 mi) from the peak.[8]

Nicolson retreated to Patna on the Ganges to perform the necessary calculations based on his observations. His raw data gave an average height of 9,200 m (30,200 ft) for peak "b", but this did not consider light refraction, which distorts heights. However, the number clearly indicated, that peak "b" was higher than Kangchenjunga. Then, Nicolson contracted malaria and was forced to return home without finishing his calculations. 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.[8]

Aerial photo of Everest from the south, behind Nuptse and Lhotse In 1852, stationed at the survey 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.[9] 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 28,156 ft (8,582 m), while Peak XV was given the height of 29,002 ft (8,840 m). Waugh concluded that Peak XV was "most probably the highest in the world".[8] Peak XV (measured in feet) was calculated to be exactly 29,000 ft (8,839.2 m) high, but was publicly declared to be 29,002 ft (8,839.8 m) in order to avoid the impression that an exact height of 29,000 feet (8,839.2 m) was nothing more than a rounded estimate.[10] Waugh is therefore wittily credited with being "the first person to put two feet on top of Mount Everest".

Name

Kangshung Face (the east face) as seen from orbit Mount Everest Everest North Face toward Base Camp Tibet Luca Galuzzi 2006.jpg The north face of Mount Everest Chomolungma[12][13] Traditional Chinese	珠穆朗瑪峰 Simplified Chinese	珠穆朗玛峰[11] Literal meaning	Chomolungma Peak [show]Transcriptions Tibetan name Tibetan	ཇོ་མོ་གླང་མ [show]Transcriptions Nepali name Nepali	सगरमाथा[14] Nepali Romanisation name Nepali Romanisation	Sagarmāthā British Survey name British Survey	Peak XV While the survey wanted to preserve local names if possible (e.g. Kangchenjunga and Dhaulagiri), Waugh argued that he could not find any commonly used local name. Waugh's search for a local name was hampered by Nepal and Tibet's exclusion of foreigners. Many local names existed, including "Deodungha" ("Holy Mountain") in Darjeeling[15] and the Tibetan "Chomolungma", which appeared on a 1733 map published in Paris by the French geographer D'Anville. In the late 19th century, many European cartographers further believed (incorrectly) that a native name for the mountain was "Gaurisankar".[16] (Gauri Sankar is a mountain between Kathmandu and Everest.)

Waugh argued that because there were many local names, it would be difficult to favour one name over all others, so he decided that Peak XV should be named after George Everest, his predecessor as Surveyor General of India.[8][17][18]

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.[8] The modern pronunciation of Everest /ˈɛvərɨst, ˈɛvrɨst/[19] is different from Sir George's pronunciation of his surname, which was /ˈiːvrɨst/ (EEV-rist).[20]

The Tibetan name for Mount Everest is ཇོ་མོ་གླང་མ (IPA: [t͡ɕʰòmòlɑ́ŋmɑ̀],[citation needed] lit. "Holy Mother"), whose official pinyin romanization is Qomolangma. It is also popularly romanised as Chomolungma and (in Wylie) as Jo-mo-glang-ma or Jomo Langma.[25] The official Chinese transcription is 珠穆朗玛峰 (t 珠穆朗瑪峰), whose pinyin form is Zhūmùlǎngmǎ Fēng ("Chomolungma Peak").[26] It is also infrequently simply translated into Chinese as Shèngmǔ Fēng (t 聖母峰, s 圣母峰, lit. "Holy Mother Peak"). In 2002, the Chinese People's Daily newspaper published an article making a case against the use of "Mount Everest" for the mountain in English, insisting that it should be referred to as "Mount Qomolangma",[26] based on the local Tibetan name. The article argued that British colonialists did not "first discover" the mountain, as it had been known to the Tibetans and mapped by the Chinese as "Qomolangma" since at least 1719.[27]

In the early 1960s, the Nepalese government coined a Nepali name for Mount Everest, Sagarmāthā or Sagar-Matha[28] (सगरमाथा[29]), allegedly to supplant the Tibetan name among the locals, which the Nepali government felt was "not acceptable".[citation needed]

Surveys

Published by the Survey of Nepal, this is Map 50 of the 57 map set at 1:50,000 scale "attached to the main text on the First Joint Inspection Survey, 1979–80, Nepal-China border." In the top center, note the boundary line, identified as separating "China" and "Nepal", passing exactly through the summit contour. The boundary here and for much of the China-Nepal border follows the main Himalayan watershed divide. The 8,848 m (29,029 ft) height given is officially recognised by Nepal and China,[30] although Nepal is planning a new survey.[31]

In 1856, Andrew Waugh announced Everest (then known as Peak XV) as 29,002 ft (8,840 m) high, after several years of calculations based on observations made by the Great Trigonometric Survey.

The elevation of 8,848 m (29,029 ft) was first determined by an Indian survey in 1955, made closer to the mountain, also using theodolites.[citation needed] It was subsequently reaffirmed by a 1975 Chinese measurement 8,848.13 m (29,029.30 ft).[32] 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.[33] Although it has not been officially recognized by Nepal,[34] 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.[35]

On 9 October 2005, after several months of measurement and calculation, the Chinese Academy of Sciences and State Bureau of Surveying and Mapping officially announced the height of Everest as 8,844.43 m (29,017.16 ft) with accuracy of ±0.21 m (0.69 ft). They claimed it was the most accurate and precise measurement to date.[36] 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 (11 ft),[32] which is in agreement with a net elevation of 8,848 m (29,029 ft). The snow and ice thickness varies over time, making a definitive height of the snow cap impossible to determine.

2004 photo mosaic the Himalayas with Makalu and Mount Everest from the International Space Station, Expedition 8. It is thought that the plate tectonics of the area are adding to the height and moving the summit northeastwards. Two accounts suggest the rates of change are 4 mm (0.16 in) per year (upwards) and 3 to 6 mm (0.12 to 0.24 in) per year (northeastwards),[33][37] but another account mentions more lateral movement (27 mm or 1.1 in),[38] and even shrinkage has been suggested.[39]

Comparisons PIA15292-Fig2-MarsMountSharp-HeightComparison.jpg The summit of Everest is the point at which Earth's surface reaches the greatest distance above sea level. Several other mountains are sometimes claimed as alternative "tallest mountains on Earth". Mauna Kea in Hawaii is tallest when measured from its base;[40] it rises over 10,200 m (33,464.6 ft) when measured from its base on the mid-ocean floor, but only attains 4,205 m (13,796 ft) above sea level.

By the same measure of base to summit, Mount McKinley, in Alaska, is also taller than Everest.[40] Despite its height above sea level of only 6,168 m (20,236 ft), Mount McKinley sits atop a sloping plain with elevations from 300 to 900 m (980 to 2,950 ft), yielding a height above base in the range of 5,300 to 5,900 m (17,400 to 19,400 ft); a commonly quoted figure is 5,600 m (18,400 ft).[41][42] By comparison, reasonable base elevations for Everest range from 4,200 m (13,800 ft) on the south side to 5,200 m (17,100 ft) on the Tibetan Plateau, yielding a height above base in the range of 3,650 to 4,650 m (11,980 to 15,260 ft).[35]

The summit of Chimborazo in Ecuador is 2,168 m (7,113 ft) farther from Earth's centre (6,384.4 km (3,967.1 mi)) than that of Everest (6,382.3 km (3,965.8 mi)), because Earth bulges at the Equator.[6] This is despite Chimborazo having a peak 6,268 m (20,564.3 ft) above sea level versus Mount Everest's 8,848 m (29,028.9 ft).

Geology

Mount Everest Geologists have subdivided the rocks comprising Mount Everest into three units called "formations".[43][44] Each formation is separated from the other by low-angle faults, called "detachments", along which they have been thrust southward 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 (28,200 ft) 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, Ordovician limestone inter layered with subordinate beds of recrystallized dolomite with argillaceous laminae and siltstone. Gansser first reported finding microscopic fragments of crinoids in this limestone.[45] Later petrographic analysis of samples of the 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. A thick, white-weathering thrombolite bed that is 60 m (200 ft) thick comprises the foot of the "Third Step", and base of the summit pyramid of Everest. This bed, which crops out starting about 70 m (230 ft) below the summit of Mount Everest, consists of sediments trapped, bound, and cemented by the biofilms of micro-organisms, especially cyanobacteria, in shallow marine waters. The Qomolangma Formation is broken up by several high-angle faults that terminate at the low angle normal fault, the Qomolangma Detachment. This detachment separates it from the underlying Yellow Band. The lower five meters of the Qomolangma Formation overlying this detachment are very highly deformed.[43][44][46]

The bulk of Mount Everest, between 7,000 and 8,600 m (23,000 and 28,200 ft), consists of the North Col Formation, of which the Yellow Band forms its upper part between 8,200 to 8,600 m (26,900 to 28,200 ft). The Yellow Band consists of intercalated beds of Middle Cambrian diopside-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 (27,200 ft) found it to consist as much as five percent of the ghosts of recrystallized crinoid ossicles. The upper five meters of the Yellow Band lying adjacent to the Qomolangma Detachment is badly deformed. A 5–40 cm (2.0–15.7 in) thick fault breccia separates it from the overlying Qomolangma Formation.[43][44][46]

The remainder of the North Col Formation, exposed between 7,000 to 8,200 m (23,000 to 26,900 ft) on Mount Everest, consists of interlayered and deformed schist, phyllite, and minor marble. Between 7,600 and 8,200 m (24,900 and 26,900 ft), 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 (23,000 and 24,900 ft), 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 be the result of the metamorphism of Middle to Early Cambrian 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 low-angle normal fault called the "Lhotse detachment".[43][44][46]

Below 7,000 m (23,000 ft), the Rongbuk Formation underlies the North Col Formation and forms the base of Mount Everest. It consists of sillimanite-K-feldspar grade schist and gneiss intruded by numerous sills and dikes of leucogranite ranging in thickness from 1 cm to 1,500 m (0.4 in to 4,900 ft).[44][47] These leucogranites are part of a belt of Late Oligocene–Miocene intrusive rocks known as the Higher Himalayan leucogranite. They formed as the result of partial melting of Paleoproterozoic to Ordovician high-grade metasedimentary rocks of the Higher Himalayan Sequence about 20 to 24 million years ago during the subduction of the Indian Plate.[48]

Mount Everest consists of sedimentary and metamorphic rocks that have been faulted southward over continental crust composed of Archean granulites of the Indian Plate during the Cenozoic collision of India with Asia. Current interpretations argue that the Qomolangma and North Col formations consist of marine sediments that accumulated within the continental shelf of the northern, passive continental margin of India prior to its collision with Asia. The Cenozoic collision of India with Asia subsequently deformed and metamorphosed these strata as it thrust them southward and upward.[49][50] The Rongbuk Formation consists of a sequence of high-grade metamorphic and granitic rocks that were derived from the alteration of high-grade metasedimentary rocks. During the collision of India with Asia, these rocks were thrust downward and to the north as they were overridden by other strata; heated, metamorphosed, and partially melted at depths of over 15 to 20 kilometres (9.3 to 12.4 mi) below sea level; and then forced upward to surface by thrusting towards the south between two major detachments.[51]

Flora and fauna See also: Organisms at high altitude Euophrys omnisuperstes, a minute black jumping spider, has been found at elevations as high as 6,700 metres (22,000 ft), possibly making it the highest confirmed non-microscopic permanent resident on Earth. It lurks in crevices and may 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.[52] 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 at 7,920 metres (25,980 ft)[53] scavenging on food, or even corpses, left by prior climbing expeditions. There is a moss that grows at 6,480 metres (21,260 ft) on Mount Everest.[54] It may be the highest altitude plant species.[54]

Environment Atmospheric pressure comparison Location	Pressure Olympus Mons summit	0.03 kilopascals (0.0044 psi) Mars average	0.6 kilopascals (0.087 psi) Hellas Planitia bottom	1.16 kilopascals (0.168 psi) Armstrong limit	6.25 kilopascals (0.906 psi) Mount Everest summit[55]	33.7 kilopascals (4.89 psi) Earth sea level	101.3 kilopascals (14.69 psi) Dead Sea level[56]	106.7 kilopascals (15.48 psi) Surface of Venus[57]	9.2 megapascals (1,330 psi) Besides rubbish, the degradation on Himalayan peaks and other issues concerned long-time Everest guide and climber Apa Sherpa. He said when he first started climbing Everest, the trail to the summit was covered with ice and snow. But it is now dotted with bare rocks. The melting ice has also exposed deep crevasses, making expeditions more dangerous.[58] Apa organized an expedition to remove 4,000 kg (8,800 lb) of rubbish from the lower part of the mountain and another 1,000 kg (2,200 lb) from higher areas.[58]

In 2008, a new weather station at about 8000 m altitude (26,246 feet) went online.[59] The station's first data in May 2008 were air temperature −17 °C, relative humidity 41.3%, atmospheric pressure 382.1 hPa (38.21 kPa), wind direction 262.8°, wind speed 12.8 m/s (28.6 mph), global solar radiation 711.9 watts/m2, solar UVA radiation 30.4 W/m2.[59] The project was orchestrated by Stations at High Altitude for Research on the Environment (SHARE), who also placed the Mount Everest webcam in 2011.[59][60] The weather station is located on the South Col and is solar powered.[61]

History of expeditions

Climbers pass by the Yellow Band Because Mount Everest is the highest mountain in the world, it has attracted considerable attention and climbing attempts. A set of climbing routes has been established over several decades of climbing expeditions to the mountain. Whether the mountain was climbed in ancient times is unknown; it may have been climbed in 1924.

By March 2012, Everest has been climbed 5,656 times with 223 deaths.[62] Although shorter mountains can be longer or steeper climbs, Everest is so high the jet stream can hit it. Climbers can be faced with winds beyond 200 mph when the weather shifts.[63] At certain times of the year the jet stream shifts north, providing periods of relative calm at the mountain.[64] Other dangers include blizzards and avalanches.[64]

Early attempts In 1885, Clinton Thomas Dent, president of the Alpine Club, suggested that climbing Mount Everest was possible in his book Above the Snow Line.[65]

The northern approach to the mountain was discovered by George Mallory and Guy Bullock on the initial 1921 British Reconnaissance Expedition. 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 to an altitude of 7,005 metres (22,982 ft). From there, Mallory espied a route to the top, but the party was unprepared for the great task of climbing any further and descended.

The British returned for a 1922 expedition. George Finch ("The other George") climbed using oxygen for the first time. He ascended at a remarkable speed—290 metres (951 ft) per hour, and reached an altitude of 8,320 m (27,300 ft), the first time a human climbed higher than 8,000 m. This feat 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 Geoffrey 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 8,550 m (28,050 ft), though he ascended only 30 m (98 ft) or so in the last hour. Mallory rustled up oxygen equipment for a last-ditch effort. He chose young Andrew Irvine as his partner.

Condor Films 1952.jpg 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 1 May 1999, 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 whether 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.

In 1933, Lady Houston, a British millionairess, 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.[66][67][68]

Early expeditions—such as General Charles 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 China 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.[69]

The Swiss expedition of 1952, led 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 7,986 m (26,201 ft). No attempt at an ascent of Everest was ever under consideration in this case.[70] Raymond Lambert and Sherpa Tenzing Norgay were able to reach a height of about 8,595 m (28,199 ft) on the southeast 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.[71]

First successful ascent by Tenzing and Hillary Main article: 1953 British Mount Everest Expedition

Edmund Hillary and Tenzing Norgay In 1953, a ninth British expedition, led by John Hunt, returned to Nepal. Hunt selected two climbing pairs to attempt to reach the summit. The first pair (Tom Bourdillon and Charles Evans) came within 100 m (330 ft) of the summit on 26 May 1953, but turned back after running into oxygen problems. As planned, their work in route finding and breaking trail and their caches of extra oxygen were of great aid to the following pair. Two days later, the expedition made its second and final assault on the summit with its second climbing pair, the New Zealander Edmund Hillary and Tenzing Norgay, a Nepali sherpa climber from Darjeeling, India. They reached the summit at 11:30 am local time on 29 May 1953 via the South Col Route. At the time, both acknowledged it as a team effort by the whole expedition, but Tenzing revealed a few years later that Hillary had put his foot on the summit first.[72] They paused at the summit to take photographs and buried a few sweets and a small cross in the snow before descending.

News of the expedition's success reached London on the morning of Queen Elizabeth II's coronation, 2 June. Returning to Kathmandu a few days later, Hunt (a Briton) and Hillary (a New Zealander) discovered that they had been promptly knighted in the Order of the British Empire, a KBE, for the ascent. Tenzing, a Nepali sherpa who was a citizen of India, 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. Hillary and Tenzing are also nationally recognized in Nepal, where annual ceremonies in schools and offices celebrate their accomplishment.[73]

The next successful ascent was on 23 May 1956 by Ernst Schmied and Juerg Marmet.[74] This was followed by Dölf Reist and Hans-Rudolf von Gunten on 24 May 1957.[74] After this, the next summiting was not until Jim Whittaker and Nawang Gombu on 1 May 1963[75][76]

Routes Mt. Everest has two main climbing routes, the southeast ridge from Nepal and the north ridge from Tibet, as well as many other less frequently climbed routes.[77] 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 recognized of fifteen routes to the top by 1996.[77] This was, however, a route decision dictated more by politics than by design as the Chinese border was closed to the western world in the 1950s after the People's Republic of China invaded Tibet.[78]

View from space showing South Col route and North Col/Ridge route 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.[79][80] 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 extremely 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.[81] Climbing equipment and supplies are carried by yaks, dzopkyos (yak-cow hybrids) and human porters to Base Camp on the Khumbu Glacier. When Hillary and Tenzing climbed Everest in 1953, the British expedition that they were part of (over 400 climbers, porters and sherpas at that point) started from the 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. During that time, Sherpas and some expedition climbers 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 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).

Climber traversing Khumbu Icefall 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 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.[82]

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 the 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 meters of rope for traversing it.[82]

On the South Col, climbers enter the death zone. Climbers typically only have a maximum of two or three days that 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.

verest base camp.jpg A view of Everest southeast ridge base camp. The Khumbu Icefall can be seen in the left. In the center are the remnants of a helicopter that crashed in 2003.

Panoramic view of Sagarmatha National Park-Gorak Shep to Pheriche.