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World's Highest Mountain Mt. Everest (SAGARMATHA)

Mount Everest, Sanskrit and Nepali Sagarmatha, Tibetan Chomolungma, Chinese (Pinyin) Zhumulangma Feng or (Wade-Giles romanization) Chu-mu-lang-ma Feng, also spelled Qomolangma Feng, mountain on the crest of the Great Himalayas of southern Asia that lies on the border between Nepal and the Tibet Autonomous Region of China, at 27°59′ N 86°56′ E. Reaching an elevation of 29,032 feet (8,849 metres), Mount Everest is the highest mountain in the world.

Like other high peaks in the region, Mount Everest has long been revered by local peoples. Its most common Tibetan name, Chomolungma, means "Goddess Mother of the World" or "Goddess of the Valley." The Sanskrit name Sagarmatha means literally "Peak of Heaven." Its identity as the highest point on the Earth's surface was not recognized, however, until 1852, when the governmental Survey of India established that fact. In 1865 the mountain—previously referred to as Peak XV—was renamed for Sir George Everest, British surveyor general of India from 1830 to 1843.

The Himalayan ranges were thrust upward by tectonic action as the Indian-Australian Plate moved northward from the south and was subducted (forced downward) under the Eurasian Plate following the collision of the two plates between about 40 and 50 million years ago. The Himalayas themselves started rising about 25 to 30 million years ago, and the Great Himalayas began to take their present form during the Pleistocene Epoch (about 2,600,000 to 11,700 years ago). Everest and its surrounding peaks are part of a large mountain massif that forms a focal point, or knot, of this tectonic action in the Great Himalayas. Information from global positioning instruments in place on Everest since the late 1990s indicates that the mountain continues to move a few inches to the northeast and rise a fraction of an inch each year.

Everest is composed of multiple layers of rock folded back on themselves (nappes). Rock on the lower elevations of the mountain consists of metamorphic schists and gneisses, topped by igneous granites. Higher up are found sedimentary rocks of marine origin (remnants of the ancient floor of the Tethys Sea that closed after the collision of the two plates). Notable is the Yellow Band, a limestone formation that is prominently visible just below the summit pyramid.

The barren Southeast, Northeast, and West ridges culminate in the Everest summit; a short distance away is the South Summit, a minor bump on the Southeast Ridge with an elevation of 28,700 feet (8,748 metres). The mountain can be seen directly from its northeastern side, where it rises about 12,000 feet (3,600 metres) above the Plateau of Tibet. The peak of Changtse (24,803 feet [7,560 metres]) rises to the north. Khumbutse (21,867 feet [6,665 metres]), Nuptse (25,791 feet [7,861 metres]), and Lhotse (27,940 feet [8,516 metres]) surround Everest's base to the west and south.

 

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Mount Everest

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HomeGeography & TravelPhysical Geography of LandMountains & Volcanoes

Mount Everest

mountain, Asia

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Alternate titles: Chomolungma, Chu-mu-lang-ma Feng, Peak XV, Qomolangma Feng, Sagarmatha, Zhumulangma Feng

By Stephen Venables See All • Last Updated: May 12, 2022 • Edit History

Table of Contents

Top Questions

What is the height of Mount Everest?

Who made the first solo ascent of Mount Everest?

Where is Mount Everest located?

Who was the first woman who climbed Mount Everest?

What are other names for Mount Everest?

Summary

Read a brief summary of this topic

Mount Everest© Arsgera/iStock.com

Mount EverestEncyclopædia Britannica, Inc.

Mount Everest, Sanskrit and Nepali Sagarmatha, Tibetan Chomolungma, Chinese (Pinyin) Zhumulangma Feng or (Wade-Giles romanization) Chu-mu-lang-ma Feng, also spelled Qomolangma Feng, mountain on the crest of the Great Himalayas of southern Asia that lies on the border between Nepal and the Tibet Autonomous Region of China, at 27°59′ N 86°56′ E. Reaching an elevation of 29,032 feet (8,849 metres), Mount Everest is the highest mountain in the world.

Mount EverestEncyclopædia Britannica, Inc./Kenny Chmielewski

Like other high peaks in the region, Mount Everest has long been revered by local peoples. Its most common Tibetan name, Chomolungma, means "Goddess Mother of the World" or "Goddess of the Valley." The Sanskrit name Sagarmatha means literally "Peak of Heaven." Its identity as the highest point on the Earth's surface was not recognized, however, until 1852, when the governmental Survey of India established that fact. In 1865 the mountain—previously referred to as Peak XV—was renamed for Sir George Everest, British surveyor general of India from 1830 to 1843.

BRITANNICA QUIZ

Mount Everest

Mount Everest, the highest point on Earth, has long been a place of fascination and an alluring draw for climbers and adventure seekers. See what you know about this extraordinary place and the feats of people who have been there.

Physical features

Geology and relief

Mount Everest massif© Marta/stock.adobe.com

The Himalayan ranges were thrust upward by tectonic action as the Indian-Australian Plate moved northward from the south and was subducted (forced downward) under the Eurasian Plate following the collision of the two plates between about 40 and 50 million years ago. The Himalayas themselves started rising about 25 to 30 million years ago, and the Great Himalayas began to take their present form during the Pleistocene Epoch (about 2,600,000 to 11,700 years ago). Everest and its surrounding peaks are part of a large mountain massif that forms a focal point, or knot, of this tectonic action in the Great Himalayas. Information from global positioning instruments in place on Everest since the late 1990s indicates that the mountain continues to move a few inches to the northeast and rise a fraction of an inch each year.

Everest is composed of multiple layers of rock folded back on themselves (nappes). Rock on the lower elevations of the mountain consists of metamorphic schists and gneisses, topped by igneous granites. Higher up are found sedimentary rocks of marine origin (remnants of the ancient floor of the Tethys Sea that closed after the collision of the two plates). Notable is the Yellow Band, a limestone formation that is prominently visible just below the summit pyramid.

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The barren Southeast, Northeast, and West ridges culminate in the Everest summit; a short distance away is the South Summit, a minor bump on the Southeast Ridge with an elevation of 28,700 feet (8,748 metres). The mountain can be seen directly from its northeastern side, where it rises about 12,000 feet (3,600 metres) above the Plateau of Tibet. The peak of Changtse (24,803 feet [7,560 metres]) rises to the north. Khumbutse (21,867 feet [6,665 metres]), Nuptse (25,791 feet [7,861 metres]), and Lhotse (27,940 feet [8,516 metres]) surround Everest's base to the west and south.

Everest is shaped like a three-sided pyramid. The three generally flat planes constituting the sides are called faces, and the line by which two faces join is known as a ridge. The North Face rises above Tibet and is bounded by the North Ridge (which meets the Northeast Ridge) and the West Ridge; key features of this side of the mountain include the Great and Hornbein couloirs (steep gullies) and the North Col at the start of the North Ridge. The Southwest Face rises above Nepal and is bounded by the West Ridge and the Southeast Ridge; notable features on this side include the South Col (at the start of the Southeast Ridge) and the Khumbu Icefall, the latter a jumble of large blocks of ice that has long been a daunting challenge for climbers. The East Face—or Kangshung (Kangxung) Face—also rises above Tibet and is bounded by the Southeast Ridge and the Northeast Ridge.

The summit of Everest itself is covered by rock-hard snow surmounted by a layer of softer snow that fluctuates annually by some 5–20 feet (1.5–6 metres); the snow level is highest in September, after the monsoon, and lowest in May after having been depleted by the strong northwesterly winter winds. The summit and upper slopes sit so high in the Earth's atmosphere that the amount of breathable oxygen there is one-third what it is at sea level. Lack of oxygen, powerful winds, and extremely cold temperatures preclude the development of any plant or animal life there.

Glaciers cover the slopes of Everest to its base. Individual glaciers flanking the mountain are the Kangshung Glacier to the east; the East, Central, and West Rongbuk (Rongpu) glaciers to the north and northwest; the Pumori Glacier to the northwest; and the Khumbu Glacier to the west and south, which is fed by the glacier bed of the Western Cwm, an enclosed valley of ice between Everest and the Lhotse-Nuptse Ridge to the south. Glacial action has been the primary force behind the heavy and continuous erosion of Everest and the other high Himalayan peaks.

Mount Everest

Table of Contents

HomeGeography & TravelPhysical Geography of LandMountains & Volcanoes

Mount Everest

mountain, Asia

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Alternate titles: Chomolungma, Chu-mu-lang-ma Feng, Peak XV, Qomolangma Feng, Sagarmatha, Zhumulangma Feng

By Stephen Venables See All • Last Updated: May 12, 2022 • Edit History

Table of Contents

Top Questions

What is the height of Mount Everest?

Who made the first solo ascent of Mount Everest?

Where is Mount Everest located?

Who was the first woman who climbed Mount Everest?

What are other names for Mount Everest?

Summary

Read a brief summary of this topic

Mount Everest© Arsgera/iStock.com

Mount EverestEncyclopædia Britannica, Inc.

Mount Everest, Sanskrit and Nepali Sagarmatha, Tibetan Chomolungma, Chinese (Pinyin) Zhumulangma Feng or (Wade-Giles romanization) Chu-mu-lang-ma Feng, also spelled Qomolangma Feng, mountain on the crest of the Great Himalayas of southern Asia that lies on the border between Nepal and the Tibet Autonomous Region of China, at 27°59′ N 86°56′ E. Reaching an elevation of 29,032 feet (8,849 metres), Mount Everest is the highest mountain in the world.

Mount EverestEncyclopædia Britannica, Inc./Kenny Chmielewski

Like other high peaks in the region, Mount Everest has long been revered by local peoples. Its most common Tibetan name, Chomolungma, means "Goddess Mother of the World" or "Goddess of the Valley." The Sanskrit name Sagarmatha means literally "Peak of Heaven." Its identity as the highest point on the Earth's surface was not recognized, however, until 1852, when the governmental Survey of India established that fact. In 1865 the mountain—previously referred to as Peak XV—was renamed for Sir George Everest, British surveyor general of India from 1830 to 1843.

BRITANNICA QUIZ

Mount Everest

Mount Everest, the highest point on Earth, has long been a place of fascination and an alluring draw for climbers and adventure seekers. See what you know about this extraordinary place and the feats of people who have been there.

Physical features

Geology and relief

Mount Everest massif© Marta/stock.adobe.com

The Himalayan ranges were thrust upward by tectonic action as the Indian-Australian Plate moved northward from the south and was subducted (forced downward) under the Eurasian Plate following the collision of the two plates between about 40 and 50 million years ago. The Himalayas themselves started rising about 25 to 30 million years ago, and the Great Himalayas began to take their present form during the Pleistocene Epoch (about 2,600,000 to 11,700 years ago). Everest and its surrounding peaks are part of a large mountain massif that forms a focal point, or knot, of this tectonic action in the Great Himalayas. Information from global positioning instruments in place on Everest since the late 1990s indicates that the mountain continues to move a few inches to the northeast and rise a fraction of an inch each year.

Everest is composed of multiple layers of rock folded back on themselves (nappes). Rock on the lower elevations of the mountain consists of metamorphic schists and gneisses, topped by igneous granites. Higher up are found sedimentary rocks of marine origin (remnants of the ancient floor of the Tethys Sea that closed after the collision of the two plates). Notable is the Yellow Band, a limestone formation that is prominently visible just below the summit pyramid.

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The barren Southeast, Northeast, and West ridges culminate in the Everest summit; a short distance away is the South Summit, a minor bump on the Southeast Ridge with an elevation of 28,700 feet (8,748 metres). The mountain can be seen directly from its northeastern side, where it rises about 12,000 feet (3,600 metres) above the Plateau of Tibet. The peak of Changtse (24,803 feet [7,560 metres]) rises to the north. Khumbutse (21,867 feet [6,665 metres]), Nuptse (25,791 feet [7,861 metres]), and Lhotse (27,940 feet [8,516 metres]) surround Everest's base to the west and south.

Mount Everest: Khumbu IcefallLee Klopfer/Alamy

Everest is shaped like a three-sided pyramid. The three generally flat planes constituting the sides are called faces, and the line by which two faces join is known as a ridge. The North Face rises above Tibet and is bounded by the North Ridge (which meets the Northeast Ridge) and the West Ridge; key features of this side of the mountain include the Great and Hornbein couloirs (steep gullies) and the North Col at the start of the North Ridge. The Southwest Face rises above Nepal and is bounded by the West Ridge and the Southeast Ridge; notable features on this side include the South Col (at the start of the Southeast Ridge) and the Khumbu Icefall, the latter a jumble of large blocks of ice that has long been a daunting challenge for climbers. The East Face—or Kangshung (Kangxung) Face—also rises above Tibet and is bounded by the Southeast Ridge and the Northeast Ridge.

The summit of Everest itself is covered by rock-hard snow surmounted by a layer of softer snow that fluctuates annually by some 5–20 feet (1.5–6 metres); the snow level is highest in September, after the monsoon, and lowest in May after having been depleted by the strong northwesterly winter winds. The summit and upper slopes sit so high in the Earth's atmosphere that the amount of breathable oxygen there is one-third what it is at sea level. Lack of oxygen, powerful winds, and extremely cold temperatures preclude the development of any plant or animal life there.

Drainage and climate

Khumbu Glacier© Shawn McCullars

Glaciers cover the slopes of Everest to its base. Individual glaciers flanking the mountain are the Kangshung Glacier to the east; the East, Central, and West Rongbuk (Rongpu) glaciers to the north and northwest; the Pumori Glacier to the northwest; and the Khumbu Glacier to the west and south, which is fed by the glacier bed of the Western Cwm, an enclosed valley of ice between Everest and the Lhotse-Nuptse Ridge to the south. Glacial action has been the primary force behind the heavy and continuous erosion of Everest and the other high Himalayan peaks.

The mountain's drainage pattern radiates to the southwest, north, and east. The Khumbu Glacier melts into the Lobujya (Lobuche) River of Nepal, which flows southward as the Imja River to its confluence with the Dudh Kosi River. In Tibet the Rong River originates from the Pumori and Rongbuk glaciers and the Kama River from the Kangshung Glacier: both flow into the Arun River, which cuts through the Himalayas into Nepal. The Rong, Dudh Kosi, and Kama river valleys form, respectively, the northern, southern, and eastern access routes to the summit.

Mount Everest

Table of Contents

HomeGeography & TravelPhysical Geography of LandMountains & Volcanoes

Mount Everest

mountain, Asia

Actions

Alternate titles: Chomolungma, Chu-mu-lang-ma Feng, Peak XV, Qomolangma Feng, Sagarmatha, Zhumulangma Feng

By Stephen Venables See All • Last Updated: May 12, 2022 • Edit History

Table of Contents

Top Questions

What is the height of Mount Everest?

Who made the first solo ascent of Mount Everest?

Where is Mount Everest located?

Who was the first woman who climbed Mount Everest?

What are other names for Mount Everest?

Summary

Read a brief summary of this topic

Mount Everest© Arsgera/iStock.com

Mount EverestEncyclopædia Britannica, Inc.

Mount Everest, Sanskrit and Nepali Sagarmatha, Tibetan Chomolungma, Chinese (Pinyin) Zhumulangma Feng or (Wade-Giles romanization) Chu-mu-lang-ma Feng, also spelled Qomolangma Feng, mountain on the crest of the Great Himalayas of southern Asia that lies on the border between Nepal and the Tibet Autonomous Region of China, at 27°59′ N 86°56′ E. Reaching an elevation of 29,032 feet (8,849 metres), Mount Everest is the highest mountain in the world.

Mount EverestEncyclopædia Britannica, Inc./Kenny Chmielewski

Like other high peaks in the region, Mount Everest has long been revered by local peoples. Its most common Tibetan name, Chomolungma, means "Goddess Mother of the World" or "Goddess of the Valley." The Sanskrit name Sagarmatha means literally "Peak of Heaven." Its identity as the highest point on the Earth's surface was not recognized, however, until 1852, when the governmental Survey of India established that fact. In 1865 the mountain—previously referred to as Peak XV—was renamed for Sir George Everest, British surveyor general of India from 1830 to 1843.

BRITANNICA QUIZ

Mount Everest

Mount Everest, the highest point on Earth, has long been a place of fascination and an alluring draw for climbers and adventure seekers. See what you know about this extraordinary place and the feats of people who have been there.

Physical features

Geology and relief

Mount Everest massif© Marta/stock.adobe.com

The Himalayan ranges were thrust upward by tectonic action as the Indian-Australian Plate moved northward from the south and was subducted (forced downward) under the Eurasian Plate following the collision of the two plates between about 40 and 50 million years ago. The Himalayas themselves started rising about 25 to 30 million years ago, and the Great Himalayas began to take their present form during the Pleistocene Epoch (about 2,600,000 to 11,700 years ago). Everest and its surrounding peaks are part of a large mountain massif that forms a focal point, or knot, of this tectonic action in the Great Himalayas. Information from global positioning instruments in place on Everest since the late 1990s indicates that the mountain continues to move a few inches to the northeast and rise a fraction of an inch each year.

Everest is composed of multiple layers of rock folded back on themselves (nappes). Rock on the lower elevations of the mountain consists of metamorphic schists and gneisses, topped by igneous granites. Higher up are found sedimentary rocks of marine origin (remnants of the ancient floor of the Tethys Sea that closed after the collision of the two plates). Notable is the Yellow Band, a limestone formation that is prominently visible just below the summit pyramid.

Get a Britannica Premium subscription and gain access to exclusive content.Subscribe Now

The barren Southeast, Northeast, and West ridges culminate in the Everest summit; a short distance away is the South Summit, a minor bump on the Southeast Ridge with an elevation of 28,700 feet (8,748 metres). The mountain can be seen directly from its northeastern side, where it rises about 12,000 feet (3,600 metres) above the Plateau of Tibet. The peak of Changtse (24,803 feet [7,560 metres]) rises to the north. Khumbutse (21,867 feet [6,665 metres]), Nuptse (25,791 feet [7,861 metres]), and Lhotse (27,940 feet [8,516 metres]) surround Everest's base to the west and south.

Mount Everest: Khumbu IcefallLee Klopfer/Alamy

Everest is shaped like a three-sided pyramid. The three generally flat planes constituting the sides are called faces, and the line by which two faces join is known as a ridge. The North Face rises above Tibet and is bounded by the North Ridge (which meets the Northeast Ridge) and the West Ridge; key features of this side of the mountain include the Great and Hornbein couloirs (steep gullies) and the North Col at the start of the North Ridge. The Southwest Face rises above Nepal and is bounded by the West Ridge and the Southeast Ridge; notable features on this side include the South Col (at the start of the Southeast Ridge) and the Khumbu Icefall, the latter a jumble of large blocks of ice that has long been a daunting challenge for climbers. The East Face—or Kangshung (Kangxung) Face—also rises above Tibet and is bounded by the Southeast Ridge and the Northeast Ridge.

The summit of Everest itself is covered by rock-hard snow surmounted by a layer of softer snow that fluctuates annually by some 5–20 feet (1.5–6 metres); the snow level is highest in September, after the monsoon, and lowest in May after having been depleted by the strong northwesterly winter winds. The summit and upper slopes sit so high in the Earth's atmosphere that the amount of breathable oxygen there is one-third what it is at sea level. Lack of oxygen, powerful winds, and extremely cold temperatures preclude the development of any plant or animal life there.

Drainage and climate

Khumbu Glacier© Shawn McCullars

Glaciers cover the slopes of Everest to its base. Individual glaciers flanking the mountain are the Kangshung Glacier to the east; the East, Central, and West Rongbuk (Rongpu) glaciers to the north and northwest; the Pumori Glacier to the northwest; and the Khumbu Glacier to the west and south, which is fed by the glacier bed of the Western Cwm, an enclosed valley of ice between Everest and the Lhotse-Nuptse Ridge to the south. Glacial action has been the primary force behind the heavy and continuous erosion of Everest and the other high Himalayan peaks.

The mountain's drainage pattern radiates to the southwest, north, and east. The Khumbu Glacier melts into the Lobujya (Lobuche) River of Nepal, which flows southward as the Imja River to its confluence with the Dudh Kosi River. In Tibet the Rong River originates from the Pumori and Rongbuk glaciers and the Kama River from the Kangshung Glacier: both flow into the Arun River, which cuts through the Himalayas into Nepal. The Rong, Dudh Kosi, and Kama river valleys form, respectively, the northern, southern, and eastern access routes to the summit.

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The climate of Everest is always hostile to living things. The warmest average daytime temperature (in July) is only about −2 °F (−19 °C) on the summit; in January, the coldest month, summit temperatures average −33 °F (−36 °C) and can drop as low as −76 °F (−60 °C). Storms can come up suddenly, and temperatures can plummet unexpectedly. The peak of Everest is so high that it reaches the lower limit of the jet stream, and it can be buffeted by sustained winds of more than 100 miles (160 km) per hour. Precipitation falls as snow during the summer monsoon (late May to mid-September). The risk of frostbite to climbers on Everest is extremely high.

The height of Everest

Controversy over the exact elevation of the summit developed because of variations in snow level, gravity deviation, and light refraction. The figure 29,028 feet (8,848 metres), plus or minus a fraction, was established by the Survey of India between 1952 and 1954 and became widely accepted. This value was used by most researchers, mapping agencies, and publishers until 1999.

Attempts were subsequently made to remeasure the mountain's height. A Chinese survey in 1975 obtained the figure of 29,029.24 feet (8,848.11 metres), and an Italian survey, using satellite surveying techniques, obtained a value of 29,108 feet (8,872 metres) in 1987, but questions arose about the methods used. In 1992 another Italian survey, using the Global Positioning System (GPS) and laser measurement technology, yielded the figure 29,023 feet (8,846 metres) by subtracting from the measured height 6.5 feet (2 metres) of ice and snow on the summit, but the methodology used was again called into question.

In 1999 an American survey, sponsored by the (U.S.) National Geographic Society and others, took precise measurements using GPS equipment. Their finding of 29,035 feet (8,850 metres), plus or minus 6.5 feet (2 metres), was accepted by the society and by various specialists in the fields of geodesy and cartography. The Chinese mounted another expedition in 2005 that utilized ice-penetrating radar in conjunction with GPS equipment. The result of this was what the Chinese called a "rock height" of 29,017.12 feet (8,844.43 metres), which, though widely reported in the media, was recognized only by China for the next several years. Nepal in particular disputed the Chinese figure, preferring what was termed the "snow height" of 29,028 feet. In April 2010 China and Nepal agreed to recognize the validity of both figures. In December 2020 China and Nepal jointly declared that the height of Everest was 29,031.69 feet (8,848.86 metres). This new measurement, derived from data from surveys performed by Nepal in 2019 and China in 2020 that utilized GPS and BeiDou navigation technology and laser theodolites, was accepted by various specialists in the fields of geodesy and cartography, including the National Geographic Society.

Human factors

Habitation

Lhotse ITed Kerasote/Photo Researchers

Everest is so tall and its climate so severe that it is incapable of supporting sustained human occupation, but the valleys below the mountain are inhabited by Tibetan-speaking peoples. Notable among these are the Sherpas, who live in villages at elevations up to about 14,000 feet (4,270 metres) in the Khumbu valley of Nepal and other locations. Traditionally an agricultural people with little cultivable land at their disposal, the Sherpas for years were traders and led a seminomadic lifestyle in their search for pastureland. In summer, livestock was grazed as high as 16,000 feet (4,880 metres), while winter refuge was taken at lower elevations on sheltered ledges and along riverbanks.

Living in close proximity to the world's highest mountains, the Sherpas traditionally treated the Himalayas as sacred—building Buddhist monasteries at their base, placing prayer flags on the slopes, and establishing sanctuaries for the wildlife of the valleys that included musk deer, monal pheasant, and Himalayan partridge. Gods and demons were believed to live in the high peaks, and the Yeti (the so-called Abominable Snowman) was said to roam the lower slopes. For these reasons, the Sherpas traditionally did not climb the mountains.

However, beginning with the British expeditions of the early 20th century, surveying and portering work became available. Eventually, the respect and pay earned in mountaineering made it attractive to the Sherpas, who, being so well adapted to the high altitudes, were capable of carrying large loads of cargo over long distances. Though Sherpas and other hill people (the name Sherpa came to be applied—erroneously—to all porters) tend to outperform their foreign clients, they typically have played a subordinate role in expeditions; rarely, for example, has one of their names been associated with a pioneering route on Everest. The influx of foreign climbers—and, in far greater numbers, trekkers—has dramatically changed Sherpa life, as their livelihood increasingly has come to depend on these climbing expeditions.

Norgay TenzingStephen Venables

Environmental issues

On the Nepalese side of the international boundary, the mountain and its surrounding valleys lie within Sagarmatha National Park, a 480-square-mile (1,243-square-km) zone established in 1976. In 1979 the park was designated a UNESCO World Heritage site. The valleys contain stands of rhododendron and forests of birch and pine, while above the tree line alpine vegetation extends to the feet of the glaciers. Over the years, carelessness and excessive consumption of resources by mountaineers, as well as overgrazing by livestock, have damaged the habitats of snow leopards, lesser pandas, Tibetan bears, and scores of bird species. To counteract past abuses, various reforestation programs have been carried out by local communities and the Nepalese government.

Expeditions have removed supplies and equipment left by climbers on Everest's slopes, including hundreds of oxygen containers. A large quantity of the litter of past climbers—tons of items such as tents, cans, crampons, and human waste—has been hauled down from the mountain and recycled or discarded. However, the bodies of most of the more than 280 climbers who have died on Everest (notably on its upper slopes) have not been removed, as they are unreachable or—for those that are accessible—their weight makes carrying them down extremely difficult. Notable in the cleanup endeavour have been the efforts of the Eco Everest Expeditions, the first of which was organized in 2008 to commemorate the death that January of Everest-climbing pioneer Sir Edmund Hillary. Those expeditions also have publicized ecological issues (in particular, concerns about the effects of climate change in the region through observations that the Khumbu Icefall has been melting).

Norgay TenzingStephen VenablesThe Editors of Encyclopaedia Britannica

History of exploration

Mountaineering on Everest

The human challenge

Mount Everest© Westend61/Getty Images

Mount Everest is difficult to get to and more difficult to climb, even with the great advances made in equipment, transportation, communications, and weather forecasting since the first major expeditions in the 1920s. The mountain itself lies in a highly isolated location. There are no roads in the region on the Nepalese side, and before the 1960s all goods and supplies had to be carried long distances by humans and pack animals. Since then, airstrips built in the Khumbu valley have greatly facilitated transport to the Everest vicinity, although the higher areas have remained accessible only via footpaths. In Tibet there is now a road to the north-side Base Camp.

There are only two brief time periods when the weather on Everest is the most hospitable for an ascent. The best one is in April and May, right before the monsoon. Once the monsoon comes, the snow is too soft and the likelihood of avalanche too great. For a few weeks in September, after the monsoon, weather conditions may also permit an attempt; by October, however, the winter storms begin and persist until March, making climbing then nearly impossible.

BRITANNICA QUIZ

Mount Everest

Mount Everest, the highest point on Earth, has long been a place of fascination and an alluring draw for climbers and adventure seekers. See what you know about this extraordinary place and the feats of people who have been there.

In addition to the challenges posed by Everest's location and climate, the effects of high altitudes on the human body are extreme: the region in the Himalayas above about 25,000 feet (7,600 metres) is known as the "death zone." Climbers at such high altitude have much more rapid breathing and pulse rates (as their bodies try to obtain more oxygen). In addition, they are not able to digest food well (and often find eating unappealing), they sleep poorly, and they often find their thinking to be confused. These symptoms are manifestations of oxygen deprivation (hypoxia) in the body tissues, which makes any effort difficult and can lead to poor decisions being made in an already dangerous environment. Supplemental (bottled) oxygen breathed through a mask can partially alleviate the effects of hypoxia, but it can present an additional problem if a climber becomes used to the oxygen and then runs out while still at high altitude. (See also altitude sickness.)

Two other medical conditions can affect climbers at high elevations. High-altitude cerebral edema (HACE) occurs when the body responds to the lack of oxygen by increasing blood flow to the brain; the brain begins to swell, and coma and death may occur. High-altitude pulmonary edema (HAPE) is a similar condition in which the body circulates additional blood to the lungs; this blood begins to leak into the air sacs, and death is caused essentially by drowning. The most effective treatment for both conditions is to move the affected person to a lower elevation. It has been found that the drug dexamethasone is a useful emergency first-aid treatment when injected into stricken climbers, allowing them to regain movement (when they might otherwise be incapacitated) and thus descend.

Routes and techniques

The southern route via the Khumbu Icefall and the South Col is the one most commonly taken by climbers attempting to summit Everest. It is the route used by the 1953 British expedition when New Zealander Edmund Hillary and Sherpa Tenzing Norgay became the first men known to have reached Everest's summit. The northern route, attempted unsuccessfully by seven British expeditions in the 1920s and '30s, is also climbed. It is now generally accepted that the first successful ascent via that approach was made by a Chinese expedition in 1960, with Wang Fuzhou, Qu Yinhua, Liu Lianman, and a Tibetan, Konbu, reaching the summit. The East Face, Everest's biggest, is rarely climbed.

Perhaps because most of the early climbers on Everest had military backgrounds, the traditional method of ascending it has been called "siege" climbing. With this technique, a large team of climbers establishes a series of tented camps farther and farther up the mountain's side. For instance, on the most frequently climbed southern route, the Base Camp on the Khumbu Glacier is at an elevation of about 17,600 feet (5,400 metres). The theory is that the climbers ascend higher and higher to establish camps farther up the route, then come down to sleep at night at the camp below the one being established. (Mountain climbers express this in the phrase, "Climb high, sleep low.") This practice allows climbers to acclimatize to the high altitude. Camps are established along the route about every 1,500 feet (450 metres) of vertical elevation and are given designations of Camp I, Camp II, and so on. Finally, a last camp is set up close enough to the summit (usually about 3,000 feet [900 metres] below) to allow a small group (called the "assault" team) to reach the peak. This was the way the British organized their expeditions; most of the large commercial expeditions continue to use it—except that all paying clients are now given a chance at the summit. Essential to the siege climbing style is the logistical support given to the climbers by the Sherpas.

There had been a feeling among some early 20th-century climbers that ascending with oxygen, support from Sherpas, and a large party was "unsporting" or that it missed the point of mountain climbing. British explorer Eric Shipton expressed the view that these large expeditions caused climbers to lose their sense of the aesthetic of mountain climbing and to focus instead on only achieving the summit. Top mountaineers, disenchanted with the ponderous and predictable nature of these siege climbs, began in the 1970s to bring a more traditional "Alpine" style of climbing to the world's highest peaks; by the 1980s this included even Everest. In this approach, a small party of perhaps three or four climbers goes up and down the mountain as quickly as possible, carrying all needed gear and provisions. This lightweight approach precludes fixing miles of safety ropes and carrying heavy supplemental oxygen. Speed is of the essence. However, at least four weeks still must be spent at and around Base Camp acclimatizing to altitude before the party can consider a summit attempt.

Stephen Venables

In the 1890s British army officers Sir Francis Younghusband and Charles (C.G.) Bruce, who were stationed in India, met and began discussing the possibility of an expedition to Everest. The officers became involved with two British exploring organizations—the Royal Geographical Society (RGS) and the Alpine Club—and these groups became instrumental in fostering interest in exploring the mountain. Bruce and Younghusband sought permission to mount an Everest expedition beginning in the early 1900s, but political tensions and bureaucratic difficulties made it impossible. Though Tibet was closed to Westerners, British officer John (J.B.L.) Noel disguised himself and entered it in 1913; he eventually got within 40 miles (65 km) of Everest and was able to see the summit. His lecture to the RGS in 1919 once again generated interest in Everest, permission to explore it was requested of Tibet, and this was granted in 1920. In 1921 the RGS and the Alpine Club formed the Mount Everest Committee, chaired by Younghusband, to organize and finance the expedition. A party under Lieutenant Colonel C.K. Howard-Bury set out to explore the whole Himalayan range and find a route up Everest. The other members were G.H. Bullock, A.M. Kellas, George Mallory, H. Raeburn, A.F.R. Wollaston, Majors H.T. Morshead and O.E. Wheeler (surveyors), and A.M. Heron (geologist).

During the summer of 1921 the northern approaches to the mountain were thoroughly explored. On the approach to Everest, Kellas died of heart failure. Because Raeburn also fell ill, the high exploration devolved almost entirely upon Mallory and Bullock. Neither had Himalayan experience, and they were faced with the problem of acclimatization besides the difficulty of the terrain.

The first object was to explore the Rongbuk valley. The party ascended the Central Rongbuk Glacier, missing the narrower opening of the eastern branch and the possible line up Everest. They returned eastward for a rest at Kharta Shekar. From there they discovered a pass at 22,000 feet (6,700 metres), the Lhakpa (Lhagba), leading to the head of the East Rongbuk Glacier. The saddle north of Everest, despite its forbidding appearance, was climbed on September 24 by Mallory, Bullock, and Wheeler and named the North Col. A bitter wind prevented them from going higher, but Mallory had from there traced a potential route to the summit.

Attempt of 1922

Members of the expedition were Brigadier General C.G. Bruce (leader), Captain J.G. Bruce, C.G. Crawford, G.I. Finch, T.G. Longstaff, Mallory, Captain C.J. Morris, Major Morshead, Edward Norton, T.H. Somervell, Colonel E.I. Strutt, A.W. Wakefield, and John Noel. It was decided that the mountain must be attempted before the onset of the summer monsoon. In the spring, therefore, the baggage was carried by Sherpas across the high, windy Plateau of Tibet.

Supplies were carried from Base Camp at 16,500 feet (5,030 metres) to an advanced base at Camp III. From there, on May 13, a camp was established on the North Col. With great difficulty a higher camp was set at 25,000 feet (7,620 metres) on the sheltered side of the North Ridge. On the next morning, May 21, Mallory, Norton, and Somervell left Morshead, who was suffering from frostbite, and pushed on through trying windy conditions to 27,000 feet (8,230 metres) near the crest of the Northeast Ridge. On May 25 Finch and Captain Bruce set out from Camp III using oxygen. Finch, a protagonist of oxygen, was justified by the results. The party, with the Gurkha Tejbir Bura, established Camp V at 25,500 feet (7,772 metres). There they were stormbound for a day and two nights, but the next morning Finch and Bruce reached 27,300 feet (8,320 metres) and returned the same day to Camp III. A third attempt during the early monsoon snow ended in disaster. On June 7 Mallory, Crawford, and Somervell, with 14 Sherpas, were crossing the North Col slopes. Nine Sherpas were swept by an avalanche over an ice cliff, and seven were killed. Mallory's party was carried down 150 feet (45 metres) but not injured.

Attempt of 1924

Members of the expedition were Brigadier General Bruce (leader), Bentley Beetham, Captain Bruce, J. de V. Hazard, Major R.W.G. Hingston, Andrew Irvine, Mallory, Norton, Noel Odell, E.O. Shebbeare (transport), Somervell, and Noel (photographer). Noel devised a novel publicity scheme for financing this trip by buying all film and lecture rights for the expedition, which covered the entire cost of the venture. To generate interest in the climb, he designed a commemorative postcard and stamp; sacks of postcards were then mailed from Base Camp, mostly to schoolchildren who had requested them. This was the first of many Everest public relations ventures.

On the climb itself, because of wintry conditions, Camp IV on the North Col was established only on May 22 by a new and steeper though safer route; the party was then forced to descend. General Bruce had to return because of illness, and under Norton Camp IV was reestablished on June 1. At 25,000 feet (7,620 metres), Mallory and Captain Bruce were stopped when the Sherpas became exhausted. On June 4 Norton and Somervell, with three Sherpas, pitched Camp VI at 26,800 feet (8,170 metres); the next day they reached 28,000 feet (8,535 metres). Norton went on to 28,100 feet (8,565 metres), a documented height unsurpassed until 1953. Mallory and Irvine, using oxygen, set out from the North Col on June 6. On June 8 they started for the summit. Odell, who had come up that morning, believed he saw them in early afternoon high up between the mists.

Initially, Odell claimed to have seen them at what became known as the Second Step (more recently, some have claimed that Odell was describing the Third Step), though later he was less certain exactly where it had been. On the Northeast Ridge there are three "steps"—steep rock barriers—between the elevations of 27,890 and 28,870 feet (8,500 and 8,800 metres) that make the final approach to the summit difficult. The First Step is a limestone vertical barrier about 110 feet (34 metres) high. Above that is a ledge and the Second Step, which is about 160 feet (50 metres) high. (In 1975 a Chinese expedition from the north affixed an aluminum ladder to the step that now makes climbing it much easier.) The Third Step contains another sheer section of rock about 100 feet (30 metres) high that leads to a more gradual slope to the summit. If Odell actually saw Mallory and Irvine at the Third Step at about 12:50 PM, then they would have been some 500 feet (150 metres) below the summit at that point. However, there has long been great uncertainty and considerable debate about all this, especially whether the pair made it to the top that day and if they were ascending or descending the mountain when Odell spotted them. The next morning Odell went up to search and reached Camp VI on June 10, but he found no trace of either man.

When Mallory was asked why he wanted to climb Everest, he replied with the famous line, "Because it's there." The British public had come to admire the determined climber over the course of his three expeditions, and they were shocked by his disappearance. (The fate of Mallory remained a mystery for 75 years; see Finding Mallory and commemorating the historic ascents.)

Attempt of 1933

Members of the expedition were Hugh Ruttledge (leader), Captain E. St. J. Birnie, Lieutenant Colonel H. Boustead, T.A. Brocklebank, Crawford, C.R. Greene, Percy Wyn-Harris, J.L. Longland, W.W. McLean, Shebbeare (transport), Eric Shipton, Francis S. Smythe, Lawrence R. Wager, G. Wood-Johnson, and Lieutenants W.R. Smyth-Windham and E.C. Thompson (wireless).

High winds made it extremely difficult to establish Base Camp in the North Col, but it was finally done on May 1. Its occupants were cut off from the others for several days. On May 22, however, Camp V was placed at 25,700 feet (7,830 metres); again storms set in, retreat was ordered, and V was not reoccupied until the 28th. On the 29th Wyn-Harris, Wager, and Longland pitched Camp VI at 27,400 feet (8,350 metres). On the way down, Longland's party, caught in a blizzard, had great difficulty.

On May 30, while Smythe and Shipton came up to Camp V, Wyn-Harris and Wager set off from Camp VI. A short distance below the crest of the Northeast Ridge, they found Irvine's ice ax. They reckoned that the Second Step was impossible to ascend and were compelled to follow Norton's 1924 traverse to the Great Couloir splitting the face below the summit. They crossed the gorge to a height about the same as Norton's but then had to return. Smythe and Shipton made a final attempt on June 1. Shipton returned to Camp V. Smythe pushed on alone, crossed the couloir, and reached the same height as Wyn-Harris and Wager. On his return the monsoon ended operations.

Also in 1933 a series of airplane flights were conducted over Everest—the first occurring on April 3—which permitted the summit and surrounding landscape to be photographed. In 1934 Maurice Wilson, an inexperienced climber who was obsessed with the mountain, died above Camp III attempting to climb Everest alone.

Reconnaissance of 1935

In 1935 an expedition led by Shipton was sent to reconnoitre the mountain, explore the western approaches, and discover more about monsoon conditions. Other members were L.V. Bryant, E.G.H. Kempson, M. Spender (surveyor), H.W. Tilman, C. Warren, and E.H.L. Wigram. In late July the party succeeded in putting a camp on the North Col, but dangerous avalanche conditions kept them off the mountain. One more visit was paid to the North Col area in an attempt on Changtse (the north peak). During the reconnaissance Wilson's body was found and buried; his diary was also recovered.

Attempts of 1936 and 1938

Members of the 1936 expedition were Ruttledge (leader), J.M.L. Gavin, Wyn-Harris, G.N. Humphreys, Kempson, Morris (transport), P.R. Oliver, Shipton, Smyth-Windham (wireless), Smythe, Warren, and Wigram. This expedition had the misfortune of an unusually early monsoon. The route up to the North Col was finished on May 13, but the wind had dropped, and heavy snowfalls almost immediately after the camp was established put an end to climbing the upper part of the mountain. Several later attempts to regain the col failed.

Members of the 1938 expedition were Tilman (leader), P. Lloyd, Odell, Oliver, Shipton, Smythe, and Warren. Unlike the two previous parties, some members of this expedition used oxygen. The party arrived early, in view of the experience of 1936, but they were actually too early and had to withdraw, meeting again at Camp III on May 20. The North Col camp was pitched under snowy conditions on May 24. Shortly after, because of dangerous snow, the route was changed and a new one made up the west side of the col. On June 6 Camp V was established. On June 8, in deep snow, Shipton and Smythe with seven Sherpas pitched Camp VI, at 27,200 feet (8,290 metres), but the next day they were stopped above it by deep powder. The same fate befell Tilman and Lloyd, who made their attempt on the 11th. Lloyd benefited from an open-circuit oxygen apparatus that partly allowed him to breathe the outside air. Bad weather compelled a final retreat.

Golden age of Everest climbs

Reconnaissance of 1951

After 1938, expeditions to Everest were interrupted by World War II and the immediate postwar years. In addition, the Chinese takeover of Tibet in 1950 precluded using the northern approach. In 1951 permission was received from the Nepalese for a reconnaissance of the mountain from the south. Members of the expedition were Shipton (leader), T.D. Bourdillon, Edmund Hillary, W.H. Murray, H.E. Riddiford, and M.P. Ward. The party marched through the monsoon, reaching Namche Bazar, the chief village of Solu-Khumbu, on September 22. At Khumbu Glacier they found it possible to scale the great icefall seen by Mallory from the west. They were stopped at the top by a huge crevasse but traced a possible line up the Western Cwm (cirque, or valley) to the South Col, the high saddle between Lhotse and Everest.

Spring attempt of 1952

Expedition members were E. Wyss Dunant (leader), J.J. Asper, R. Aubert, G. Chevalley, R. Dittert (leader of climbing party), L. Flory, E. Hofstetter, P.C. Bonnant, R. Lambert, A. Roch, A. Lombard (geologist), and A. Zimmermann (botanist). This strong Swiss party first set foot on the Khumbu Icefall on April 26. After considerable difficulty with the route, they overcame the final crevasse by means of a rope bridge. The 4,000-foot (1,220-metre) face of Lhotse, which had to be climbed to reach the South Col, was attempted by a route running beside a long spur of rock christened the Éperon des Genevois. The first party, Lambert, Flory, Aubert, and Tenzing Norgay (sirdar, or leader of the porters), with five Sherpas, tried to reach the col in one day. They were compelled to bivouac quite a distance below it (May 25) and the next day reached the summit of the Éperon, at 26,300 feet (8,016 metres), whence they descended to the col and pitched camp. On May 27 the party (less the five Sherpas) climbed up the Southeast Ridge. They reached approximately 27,200 feet (8,290 metres), and there Lambert and Tenzing bivouacked. The next day they pushed on up the ridge and turned back at approximately 28,000 feet (8,535 metres). Also on May 28 Asper, Chevalley, Dittert, Hofstetter, and Roch reached the South Col, but they were prevented by wind conditions from going higher and descended to the base.

Autumn attempt of 1952

Members of this second Swiss expedition were Chevalley (leader), J. Buzio, G. Gross, Lambert, E. Reiss, A. Spöhel, and Norman Dyhrenfurth (photographer). The party found the icefall easier to climb than in the spring and had brought poles to bridge the great crevasse. Camp IV was occupied on October 20. Higher up, however, they were constantly harassed by bitterly cold winds. On the ice slope below the Éperon one Sherpa was killed, and the party took to the glaciated face of Lhotse on the right. The South Col was reached on November 19, but the summit party climbed only 300 feet (90 metres) higher before being forced to withdra