Mount Everest, known in Nepali as Sagarmāthā and in Tibetan as Chomolungma,

is Earth's highest mountain, located in the Mahalangur Himal sub-range of the Himalayas. The
international border between China (Tibet Autonomous Region) and Nepal runs across its summit
point.
The current official height of 8,848 m (29,029 ft), recognised by China and Nepal, was established
by a 1955 Indian survey and subsequently confirmed by a Chinese survey in 1975.[1] In 2005, China
remeasured the rock height of the mountain, with a result of 8844.43 m. There followed an argument
between China and Nepal as to whether the official height should be the rock height (8,844 m.,
China) or the snow height (8,848 m., Nepal). In 2010, an agreement was reached by both sides that
the height of Everest is 8,848 m, and Nepal recognises China's claim that the rock height of Everest
is 8,844 m.[6]
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. As there appeared to be
several different local names, Waugh chose to name the mountain after his predecessor in the
post, Sir George Everest, despite George Everest's objections.[7]
Mount Everest attracts many climbers, some of them highly experienced mountaineers. 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, and wind, as well as significant hazards from avalanches and the Khumbu Icefall. As of
2017, nearly 300 people have died on Everest, many of whose bodies remain on the mountain.[8]
The first recorded efforts to reach Everest's summit were made by British mountaineers. As Nepal
did not allow 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).
Seven porters were killed in an avalanche on the descent from the North Col. The 1924
expedition resulted in one of the greatest mysteries on Everest to this day: George
Mallory and Andrew Irvine made a final summit attempt on 8 June but never returned, sparking
debate as to whether or not 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 Hillarymade
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. The Chinese
mountaineering team of Wang Fuzhou, Gonpo, and Qu Yinhua made the first reported ascent of the
peak from the north ridge on 25 May 1960.[9][10]

Contents
[hide]

• 1Early surveys
• 2Name
• 3Surveys
o 3.1Comparisons
• 4Geology
• 5Flora and fauna
• 6Environment
• 7History of expeditions
o 7.1Overview
o 7.2Early attempts
 o 7.3First successful ascent by Tenzing and Hillary
o 7.41970 disaster
o 7.51979/1980: Winter Himalaism
o 7.61993: astronaut fatality
o 7.71996 disaster
o 7.82006 mountaineering season
7.8.1David Sharp ethics controversy
7.8.2Lincoln Hall rescue
o 7.92007
o 7.10Ascent statistics up to 2010 season
o 7.112012 and 2013 events
o 7.122014 avalanche and season
o 7.132015 avalanche, earthquake, season
7.13.1Mountain re-opens in August 2015
o 7.142016 season
7.14.1Rescues and fatalities
o 7.152017 season
• 8Climbing
o 8.1Permits
o 8.2Routes
8.2.1Southeast ridge
8.2.2North ridge route
o 8.3Summit
o 8.4Death zone
o 8.5Supplemental oxygen
o 8.6Autumn climbing
o 8.7Selected climbing records
o 8.8Summiting with disabilities
• 9Everest and aviation
o 9.11988: First climb and glide
o 9.21991: Hot air balloon flyover
o 9.32005: Pilot summits Everest with helicopter
o 9.42011 Paraglide off summit
o 9.52014: Helicopter-assisted ascent
o 9.62016: Helicopter business increases
• 10Financial cost of guided climbs
• 11Commercial climbing
o 11.1Law and order
• 122014 Sherpa strike
• 13Extreme sports at Mount Everest
• 14Everest and religion
• 15Waste management
• 16Names
• 17Maps
o 17.1From China (Tibet region)
o 17.2From Gokyo Ri
• 18Terrain animation
• 19See also
• 20References
• 21Further reading
• 22External links

Early surveys

Map produced in 1870 showing the triangles and transects used in the Great Trigonometric Survey of India.
The Great Trigonometrical Survey of India was started in April 1802

Location on Earth

In 1715, the Qing Empire surveyed the mountain while mapping its territory and depicted it as Mount
Qomolangma no later than 1719.[11]

Mount Everest relief map

From Kala Patthar

In 1802, the British began the Great Trigonometric Survey of India to fix the locations, heights, 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 due to suspicions of political aggression
and possible annexation. Several requests by the surveyors to enter Nepal were turned down.[12]
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 because of failing health.[12]
Nonetheless, in 1847, the British continued the survey and began detailed observations of the
Himalayan peaks from observation stations up to 240 km (150 mi) distant. 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 at the east 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
subordinates, also saw the peak from a site 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 his attempts.[12]
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.[12]
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. 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. Peak "b" now
became known as Peak XV.[12]
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.[13] 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 numbers, 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 8,582 m (28,156 ft), while Peak XV was given the height of 8,840 m (29,002 ft). Waugh
concluded that Peak XV was "most probably the highest in the world".[12] 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.[14] Waugh is sometimes playfully credited with being "the first
person to put two feet on top of Mount Everest".[15]