Mount Everest

Mount Everest, known locally as Sagarmāthā in Nepal and Qomolangma in Tibet, is the highest mountain on Earth above sea level. It is part of the Mahalangur Himal sub-range of the Himalayas and sits on the border between China and Nepal. In 2020, its height was measured to be 8,848.86 meters (29,031 feet).

The mountain attracts many climbers from around the world. There are two main routes to the summit: one from the southeast in Nepal and another from the north in Tibet. While climbing Everest is not very difficult technically, it can be very dangerous because of thin air, bad weather, strong winds, and snow slides.

The first people to reach the top of Everest were Tenzing Norgay and Edmund Hillary in 1953. They used the southeast route. Since then, many more people have climbed Everest, though the mountain remains a challenging and serious place to explore.

Name

Mount Everest has different names depending on the culture. In Nepal, it is called Sagarmāthā, meaning "goddess of the sky". In Tibet, the mountain is known as Qomolangma, which means "holy mother".

The name "Mount Everest" comes from a British surveyor named Sir George Everest. When the British were mapping the area, they couldn't find one commonly used local name, so they named the mountain after him. Before that, it was temporarily called "Peak XV". Some other names that were used by mistake or in the past include "Deodungha" and "Gaurishankar".

Surveys

In 1802, the British started the Great Trigonometrical Survey of India to measure the heights of the world's highest mountains. They used large instruments called theodolites and moved northward. However, Nepal did not allow them to enter the country.

The British continued their work from Terai, a region south of Nepal. In 1847, they began detailed observations of the Himalayan peaks. In 1852, an Indian mathematician named Radhanath Sikdar identified what is now known as Mount Everest as the world's highest peak.

In 1856, Andrew Scott Waugh announced that Mount Everest was 8,840 metres high. Later measurements updated this height. In 2020, China and Nepal agreed that the official height of Mount Everest is 8,848.86 metres.

Scientists think that plate tectonics are still pushing the mountain higher.

Geology

Mount Everest's rocks are divided into three main layers called formations, separated by faults. From the top down, these are the Qomolangma Formation, the North Col Formation, and the Rongbuk Formation. The Qomolangma Formation, near the summit, is made mostly of limestone from the Ordovician period, with some dolomite and other minerals. The North Col Formation, making up much of the mountain between 7,000 and 8,600 meters, includes marble and schist that formed from ancient sea sediments. The Rongbuk Formation at the base consists of schist and gneiss, with intrusions of granite formed millions of years ago.

The International Union of Geological Sciences recognized Mount Everest as an important geological site in 2022 because its rocks contain fossils from ancient marine life, showing its history as part of the seafloor before the Himalayas formed.

Flora and fauna

Mount Everest has very little native plants or animals. One type of moss grows as high as 6,480 metres, and it may be the highest plant found on Earth. A small black jumping spider of the genus Euophrys has been found as high as 6,700 metres, possibly the highest permanent resident on Earth. The bar-headed goose is known to fly over the Himalayas and has been seen near Everest's summit.

Yaks are often used to carry gear for climbers. Other animals in the region include the Himalayan tahr, the snow leopard, the Himalayan black bear, and the red panda.

Conservation

Everest is protected on the Nepalese side as part of Sagarmatha National Park, and on the Chinese side as part of Qomolangma National Nature Reserve.

Climate

Mount Everest has an ice cap climate, meaning all months are very cold. The mountain reaches into the upper troposphere and even touches the stratosphere. The air at the top is much thinner, about one-third of what it is at sea level. Strong jet stream winds can blow across the summit, reaching speeds up to 280 km/h (175 mph). These winds can be dangerous for climbers.

Because of climate change, the glaciers around Everest, like the Khumbu Glacier, are changing quickly. This affects where climbers set up their base camp. Scientists have placed weather stations high on the mountain to learn more about conditions there. One of the highest weather stations, called the Balcony Station, was set up near the summit but stopped sending data in 2020.

Expeditions

See also: List of people who died climbing Mount Everest

Because Everest is the highest mountain in the world, it has attracted many climbing attempts. Climbing routes have been established over decades of expeditions.

The summit was first reached by humans in 1953. Despite many efforts, only about 200 people had summited by 1987. Everest remained a difficult climb for decades. As of December 2024, records show just under 13,000 total summits by around 7,200 different people.

Everest is so high that the jet stream can hit it, creating very strong winds. Climbers can face winds over 320 km/h (200 mph) when the weather changes. Other dangers include blizzards and avalanches.

Early attempts

In 1885, Clinton Thomas Dent suggested climbing Everest was possible. The northern approach to the mountain was discovered by George Mallory and Guy Bullock in 1921. They climbed the North Col to 7,005 metres (22,982 ft).

In 1922, Mallory, Col. Felix Norton, and Howard Somervell reached 8,225 m (26,985 ft) without oxygen. Later, George Finch and Geoffrey Bruce climbed using oxygen for the first time, reaching 8,321 m (27,300 ft).

First successful ascent by Tenzing and Hillary, 1953

Main article: 1953 British Mount Everest expedition

In 1953, a British expedition led by John Hunt returned to Nepal. Two climbing pairs were selected to attempt the summit. The second pair, Edmund Hillary and Tenzing Norgay, a Nepali Sherpa climber, reached the summit on 29 May 1953 via the South Col route.

1950s–60s

In 1956, Ernst Schmied and Juerg Marmet ascended Everest. In 1960, Chinese climbers made the first ascent from the North Ridge. In 1963, the first American, Jim Whittaker, reached the summit.

1970s

In 1975, Junko Tabei became the first woman to summit Everest. In 1978, Reinhold Messner and Peter Habeler made the first ascent without supplemental oxygen.

Lho La tragedy, 1989

In 1989, an international expedition to Everest faced difficulties. Four climbers died in an avalanche near the Lho La pass.

1996 disaster

Main article: 1996 Mount Everest disaster

In May 1996, eight climbers died after being caught in a blizzard during a summit attempt. This disaster raised questions about the safety of guiding clients on Everest.

2014 avalanche

Main article: 2014 Mount Everest ice avalanche

In April 2014, an avalanche hit near Base Camp 2, killing 16 Nepali guides.

2015 avalanche and earthquake

Main article: 2015 Mount Everest avalanches

In April 2015, an earthquake triggered an avalanche at Everest Base Camp, shutting down the climbing season.

2016 and 2017

In 2016, 641 climbers reached the summit. In 2017, hundreds of climbers summited, with several reaching the milestone of 21 summits.

2018

In 2018, a record 891 climbers reached the summit, aided by favorable weather conditions.

2019

In 2019, over 890 climbers summited despite several deaths, possibly due to crowding and shorter weather windows.

2020s

In 2020, foreign climbing groups were prohibited due to the COVID-19 pandemic. In October 2025, blizzard conditions led to evacuations on the mountain.

Climbing

Permits

In 2014, Nepal issued 334 climbing permits, which were extended until 2019 due to the closure. In 2015, Nepal issued 357 permits, but the mountain was closed again because of the avalanche and earthquake, and these permits were given a two-year extension to 2017.

In 2017, a person who tried to climb Everest without the $11,000 permit was caught after he made it past the Khumbu icefall. He faced, among other penalties, a $22,000 fine and a possible four years in jail. In the end, he was allowed to return home but banned from mountaineering in Nepal for 10 years.

The number of permits issued each year by Nepal is:

• 2008: 160
• 2009: 220
• 2010: 209
• 2011: 225
• 2012: 208
• 2013: 316
• 2014: 326 (extended for use through 2019)
• 2015: 356 (extended for use through 2017)
• 2016: 289
• 2017: 366 to 373
• 2018: 346
• 2019: 381
• 2020: 0 (no permits issued during the pandemic)
• 2021: 408 (current record)

The Chinese side in Tibet is also managed with permits for summiting Everest. They did not issue permits in 2008, due to the Olympic torch relay being taken to the summit of Mount Everest.

In March 2020, the governments of China and Nepal cancelled all climbing permits for Mount Everest due to the COVID-19 pandemic. In April 2020, a group of Chinese mountaineers began an expedition from the Chinese side. The mountain remained closed on the Chinese side to all foreign climbers. On 10 May 2021, a separation line was announced by Chinese authorities to prevent the spread of coronavirus from climbers ascending Nepal's side.

In April 2025, the Government of Nepal introduced a new regulation requiring climbers to have previously summited at least one 7,000-metre peak within Nepal before being eligible to obtain a permit for an expedition to Mount Everest. The rule is scheduled to come into effect from the Spring 2026 climbing season.

Commercial climbing

According to Jon Krakauer, the era of commercialisation of Everest started in 1985, when the summit was reached by a guided expedition led by David Breashears that included Richard Bass, a wealthy 55-year-old businessman and an amateur mountain climber with four years of climbing experience. By the early-1990s, several companies were offering guided tours to the mountain. Rob Hall, one of the mountaineers who died in the 1996 disaster, had successfully guided 39 clients to the summit before that incident.^: 24, 42 

By 2016, most guiding services cost between US$35,000 and US$200,000. Going with a "celebrity guide", usually a well-known mountaineer typically with decades of climbing experience and perhaps several Everest summits, can cost over £100,000 as of 2015. However, the services offered vary widely and it is "buyer beware" when doing deals in Nepal, one of the poorest and least developed countries in the world. Tourism contributed 7.9 per cent of the gross domestic product (GDP) in 2019 in a country with high unemployment, but an Everest porter can make nearly double the nation's average wage in a region in which other sources of income are lacking.

Costs beyond the guiding service can vary widely. It is technically possible to reach the summit with minimal additional expenses, and there are "budget" travel agencies that offer logistical support for such trips. A limited support service, offering only some meals at base camp and bureaucratic overhead like a permit, can cost as little as US$7,000 as of 2007. However, this is considered difficult and dangerous.

Climbing gear required to reach the summit may cost in excess of US$8,000, and most climbers also use bottled oxygen , which adds around US$3,000. The permit to enter the Everest area from the south via Nepal costs US$10,000 to US$30,000 per person, depending on the size of the team. The ascent typically starts at one of the two base camps near the mountain, both of which are approximately 100 kilometres (60 mi) from Kathmandu and 300 kilometres (190 mi) from Lhasa (the two nearest cities with major airports). Transferring one's equipment from the airport to the base camp may add as much as US$2,000.

Many climbers hire "full service" guide companies, which provide a wide spectrum of services, including the acquisition of permits, transportation to/from base camp, food, tents, fixed ropes, medical assistance while on the mountain, an experienced mountaineer guide, and even personal porters to carry one's backpack and cook one's meals. The cost of such a guide service may range from US$40,000 to $80,000 per person. Since most equipment is moved by Sherpas, clients of full-service guide companies can often keep their backpack weights under 10 kilograms (22 lb), or hire a Sherpa to carry their backpack for them. By contrast, climbers attempting less commercialised peaks, like Denali, are often expected to carry backpacks over 30 kilograms (66 lb) and, occasionally, to tow a sled with 35 kilograms (77 lb) of gear and food.

The degree of commercialisation of Mount Everest is a frequent subject of criticism. Jamling Tenzing Norgay, the son of Tenzing Norgay, said in a 2003 interview that his late father would have been shocked to discover that rich thrill-seekers with no climbing experience were now routinely reaching the summit, "You still have to climb this mountain yourself with your feet. But the spirit of adventure is not there any more. It is lost. There are people going up there who have no idea how to put on crampons. They are climbing because they have paid someone $65,000. It is very selfish. It endangers the lives of others."

One example of this is Shriya Shah-Klorfine, who had to be taught how to put on crampons during her summit attempt in 2012. She paid at least US$40,000 to a new guiding company for the trip, and died when she ran out of oxygen during the descent after climbing for 27 hours straight.

Reinhold Messner concurred in 2004:

You could die in each climb and that meant you were responsible for yourself. We were real mountaineers: careful, aware and even afraid. By climbing mountains we were not learning how big we were. We were finding out how breakable, how weak and how full of fear we are. You can only get this if you expose yourself to high danger. I have always said that a mountain without danger is not a mountain....High altitude alpinism has become tourism and show. These commercial trips to Everest, they are still dangerous. But the guides and organisers tell clients, 'Don't worry, it's all organised.' The route is prepared by hundreds of Sherpas. Extra oxygen is available in all camps, right up to the summit. People will cook for you and lay out your beds. Clients feel safe and don't care about the risks.

By 2015, Nepal was considering requiring that climbers have some experience, hoping this would both make the mountain safer and increase revenue. One barrier to this is that low-budget firms make money not taking inexperienced climbers to the summit. Those turned away by Western firms can often find another firm willing to take them for a price—that they return home soon after arriving after base camp, or part way up the mountain.

However, not all opinions on the subject among prominent mountaineers have been strictly negative. For example, Edmund Hillary stated in 2003 that while "Having people pay $65,000 and then be led up the mountain by a couple of experienced guides...isn't really mountaineering at all", he was pleased by the changes brought to Everest area by Westerners:

I don't have any regrets because I worked very hard indeed to improve the condition for the local people. When we first went in there they didn't have any schools, they didn't have any medical facilities, all over the years we have established 27 schools, we have two hospitals and a dozen medical clinics and then we've built bridges over wild mountain rivers and put in fresh water pipelines so in cooperation with the Sherpas we've done a lot to benefit them.

One of the early guided summiters, Richard Bass (of Seven Summits fame) stated in 2003 that "Climbers should have high altitude experience before they attempt the really big mountains. People don't realise the difference between a 20,000-foot [6,100 m] mountain and 29,000-foot [8,800 m]. It's not just arithmetic. The reduction of oxygen in the air is proportionate to the altitude alright, but the effect on the human body is disproportionate—an exponential curve. People climb Denali [6,190 m or 20,320 ft] or Aconcagua [6,960 m or 22,834 ft] and think, 'Heck, I feel great up here, I'm going to try Everest.' But it's not like that."

Speed climbing

Altitude tents

Main article: Altitude tent

Some expedition teams have clients use altitude tents to pre-acclimatise prior to leaving for the mountain. Compared to traditional Everest expeditions that last 50 to 60 days, altitude tents can reduce the expedition time frame to 30 to 35 days.

Xenon gas

Further information: Xenon § Sports doping and mountaineering

In 2025, four men climbed the mountain in one week. They claimed their inhalation of xenon gas 10 days prior to stimulate erythropoietin production had eliminated the need for altitude acclimatisation over several weeks. The International Climbing and Mountaineering Federation (UIAA) criticised the decision, citing that there is no evidence that the inhalation of xenon improves performance in high elevation environments. Furthermore, the UIAA warned that as an anesthetic, xenon gas could result in impaired brain function, respiratory compromise, and death if used in an unmonitored setting.

Summiting with disabilities

Summiting Everest with disabilities has become popular in the 21st century. Sudarshan Gautam, a Canadian double-amputee, summited the mountain in 2013. In the same year, Eli Reimer, a teenager with Down syndrome, hiked to the South Base Camp as part of a fundraising effort for his father's foundation.

Routes

Mount 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. Of the two main routes, the Southeast Ridge is technically easier and more frequently used. It was the route used by Edmund Hillary and Tenzing Norgay in 1953 and the first recognised of 15 routes to the top by 1996. This was, however, a route decision dictated more by politics than by design, as the Chinese border was closed to the western world in the 1950s, after Annexation of Tibet by the People's Republic of China.

Most attempts are made during May, before the summer monsoon season. As the monsoon season approaches, the jet stream shifts northward, thereby reducing the average wind speeds high on the mountain. While attempts are sometimes made in September and October, after the monsoons, when the jet stream is again temporarily pushed northward, the additional snow deposited by the monsoons and the less stable weather patterns at the monsoons' tail end 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 acclimatisation in order to prevent altitude sickness. 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 they were part of (comprising 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, acclimatising 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).

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.

From Camp II, 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 metres 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 metres of rope for traversing it.

On the South Col, climbers enter the death zone. Climbers making summit bids typically can endure no more than two or three days at this altitude. If the weather is not clear with low winds during these short few days, climbers are forced to descend, many all the way back down to Base Camp.

From Camp IV, climbers begin their summit push around midnight, with hopes of reaching the summit (still another 1,000 metres above) within 10 to 12 hours. Climbers first reach "The Balcony" at 8,400 m (27,600 ft), a small platform where they can rest and gaze at peaks to the south and east in the early light of dawn. Continuing up the ridge, climbers are then faced with a series of imposing rock steps which usually forces them to the east into the waist-deep snow, a serious avalanche hazard. At 8,750 m (28,700 ft), a small table-sized dome of ice and snow marks the South Summit.

From the South Summit, climbers follow the knife-edge Southeast Ridge along what is known as the "Cornice traverse", where snow clings to intermittent rock. This is the most exposed section of the climb, and a misstep to the left would send one 2,400 m (7,900 ft) down the Southwest Face, while to the immediate right is the 3,050 m (10,010 ft) Kangshung Face. At the end of this traverse is an imposing 12 m (39 ft) rock wall, the Hillary Step, at 8,790 m (28,840 ft).

Hillary and Tenzing were the first climbers to ascend this step, and did so using primitive ice climbing equipment and ropes. Nowadays, climbers ascend using fixed ropes previously set up by Sherpas. Once above the step, it is a comparatively easy climb to the top on moderately angled snow slopes—though the exposure on the ridge is extreme, especially while traversing large cornices of snow. With increasing numbers climbing the mountain, the Step has frequently become a bottleneck, with climbers forced to wait significant amounts of time for their turn on the ropes, leading to problems in getting climbers efficiently up and down the mountain.^{[citation needed]}

After the Hillary Step, climbers must traverse a loose and rocky section that has a large entanglement of fixed ropes that can be troublesome in bad weather. Climbers typically spend less than half an hour at the summit to allow time to descend to Camp IV before darkness sets in, to avoid serious problems with afternoon weather, or because supplemental oxygen tanks run out.

North Ridge route

See also: Three Steps

The North Ridge route begins from the north side of Everest, in Tibet. Expeditions trek to the Rongbuk Glacier, setting up base camp at 5,180 m (16,990 ft) on a gravel plain just below the glacier. To reach Camp II, climbers ascend the medial moraine of the east Rongbuk Glacier up to the base of Changtse, at around 6,100 m (20,000 ft). Camp III (ABC – Advanced Base Camp) is situated below the North Col at 6,500 m (21,300 ft). To reach Camp IV on the North Col, climbers ascend the glacier to the foot of the col where fixed ropes are used to reach the North Col at 7,010 m (23,000 ft). From the North Col, climbers ascend the rocky North Ridge to set up Camp V at around 7,775 m (25,500 ft). The route crosses the North Face in a diagonal climb to the base of the Yellow Band, reaching the site of Camp VI at 8,230 m (27,000 ft). From Camp VI, climbers make their final summit push.

Climbers face a treacherous traverse from the base of the First Step: ascending from 8,501 to 8,534 m (27,890 to 28,000 ft), to the crux of the climb, the Second Step, ascending from 8,577 to 8,626 m (28,140 to 28,300 ft). (The Second Step includes a climbing aid called the "Chinese ladder", a metal ladder placed semi-permanently in 1975 by a party of Chinese climbers. It has been almost continuously in place since, and ladders have been used by virtually all climbers on the route.) Once above the Second Step the inconsequential Third Step is clambered over, ascending from 8,690 to 8,800 m (28,510 to 28,870 ft). Once above these steps, the summit pyramid is climbed by a snow slope of 50 degrees, to the final summit ridge along which the top is reached.

Summit

The summit of Everest has been described as "the size of a dining room table". The summit is capped with snow over ice over rock, and the layer of snow varies from year to year. The rock summit is made of Ordovician limestone and is a low-grade metamorphic rock. (See the Surveys section for more on its height and about the Everest rock summit.)

Below the summit, there is an area known as "rainbow valley", filled with dead bodies still wearing brightly coloured winter gear. Down to about 8,000 m (26,000 ft) is an area commonly called the "death zone", due to the high danger and low oxygen because of the low pressure.

Death zone

See also: Effects of high altitude on humans

At the higher regions of Mount Everest, climbers seeking the summit typically spend substantial time within the death zone (altitudes higher than 8,000 m or 26,000 ft), and face significant challenges to survival. Temperatures can dip to very low levels, resulting in frostbite of any body part exposed to the air. Since temperatures are so low, snow is well-frozen in certain areas and death or injury by slipping and falling can occur. High winds at these altitudes on Everest are also a potential threat to climbers.

Another significant threat to climbers is low atmospheric pressure. The atmospheric pressure at the top of Everest is about a third of sea level pressure or 0.333 standard atmospheres (337 mbar), resulting in the availability of only about a third as much oxygen to breathe.

A sea-level dweller exposed to the atmospheric conditions at the altitude above 8,500 m (27,900 ft) without acclimatisation would likely lose consciousness within two to three minutes. At sea level, blood oxygen saturation is generally 98 to 99 per cent. At base camp, blood saturation fell to between 85 and 87 per cent. Blood samples taken at the summit indicated very low oxygen levels in the blood. A side effect of low blood oxygen is a greatly increased breathing rate, often 80–90 breaths per minute as opposed to a more typical 20–30. Exhaustion can occur merely by attempting to breathe.

Lack of oxygen, exhaustion, extreme cold, and climbing hazards all contribute to the death toll. An injured person who cannot walk is in serious trouble, since rescue by helicopter is generally impractical and carrying the person off the mountain is very risky. People who die during the climb are typically left behind. As of 2015, over 200 bodies remain on the mountain.

Debilitating symptoms consistent with high altitude cerebral oedema commonly present during descent from the summit of Mount Everest. Profound fatigue and late times in reaching the summit are early features associated with subsequent death.

— Mortality on Mount Everest, 1921–2006: descriptive study

A 2008 study noted that the "death zone" is indeed where most Everest deaths occur, but also noted that most deaths occur during descent from the summit. A 2014 article in The Atlantic about deaths on Everest noted that while falling is one of the greatest dangers the death zone presents for all 8000ers, avalanches are a more common cause of death at lower altitudes.

Despite this, Everest is safer for climbers than a number of peaks by some measurements, but it depends on the period. Some examples are Kangchenjunga, K2, Annapurna, Nanga Parbat, and the Eiger (especially the nordwand). Some factors that affect total mountain lethality include the level of popularity of the mountain, the skill of those climbing, and the difficulty of the climb.

Another health hazard is retinal haemorrhages, which can damage eyesight and cause blindness. Up to a quarter of Everest climbers can experience retinal haemorrhages, and although they usually heal within weeks of returning to lower altitudes, in 2010 a climber went blind and died in the death zone.

Supplemental oxygen

Most expeditions use oxygen masks and tanks above 8,000 m (26,247 ft). Everest can be climbed without supplementary oxygen, but only by the most accomplished mountaineers and at increased risk. Low oxygen impairs cognition, and the combination of extreme weather, low temperatures, and steep slopes often requires quick, accurate decisions. While about 95 per cent of climbers who reach the summit use bottled oxygen in order to reach the top, about five per cent of climbers have summited Everest without supplemental oxygen. The death rate is double for those who attempt to reach the summit without supplemental oxygen. Travelling above 8,000 m (26,000 ft) altitude is a factor in cerebral hypoxia. One study found that Mount Everest may be the highest an acclimatised human could go, but also found that climbers may suffer permanent neurological damage despite returning to lower altitudes.

The use of bottled oxygen to ascend Mount Everest has been controversial. It was first used on the 1922 British Mount Everest Expedition by George Finch and Geoffrey Bruce who climbed up to 7,800 m (25,600 ft) at a spectacular speed of 300 vertical metres per hour (1,000 ft/h). Pinned down by a fierce storm, they escaped death by breathing oxygen from a jury-rigged set-up during the night. The next day they climbed to 8,100 m (26,600 ft) at 270 m/h (900 ft/h) – nearly three times as fast as non-oxygen users. Yet the use of oxygen was considered so unsportsmanlike that none of the rest of the Alpine world recognised this high ascent rate.^{[citation needed]}

George Mallory described the use of such oxygen as unsportsmanlike, but he later concluded that it would be impossible for him to summit without it and consequently used it on his final attempt in 1924. When Tenzing and Hillary made the first successful summit in 1953, they also used open-circuit bottled oxygen sets, with the expedition's physiologist Griffith Pugh referring to the oxygen debate as a "futile controversy", noting that oxygen "greatly increases subjective appreciation of the surroundings, which after all is one of the chief reasons for climbing." For the next twenty-five years, bottled oxygen was considered standard for any successful summit.

...although an acclimatised lowlander can survive for a time on the summit of Everest without supplemental oxygen, one is so close to the limit that even a modicum of excess exertion may impair brain function.

— Thomas F. Hornbein in The high-altitude brain

Reinhold Messner was the first climber to break the bottled oxygen tradition and in 1978, with Peter Habeler, made the first successful climb without it. In 1980, Messner summited the mountain solo, without supplemental oxygen or any porters or climbing partners, on the more difficult northwest route. Once the climbing community was satisfied that the mountain could be climbed without supplemental oxygen, many purists then took the next logical step of insisting that is how it should be climbed.^: 154 

The aftermath of the 1996 disaster further intensified the debate. Jon Krakauer's Into Thin Air (1997) expressed the author's personal criticisms of the use of bottled oxygen. Krakauer wrote that the use of bottled oxygen allowed otherwise unqualified climbers to attempt to summit, leading to dangerous situations and more deaths. The disaster was partially caused by the sheer number of climbers (34 on that day) attempting to ascend, causing bottlenecks at the Hillary Step and delaying many climbers, most of whom summited after the usual 14:00 turnaround time. He proposed banning bottled oxygen except for emergency cases, arguing that this would both decrease the growing pollution on Everest—many bottles have accumulated on its slopes—and keep marginally qualified climbers off the mountain.

The 1996 disaster also introduced the issue of the guide's role in using bottled oxygen.

Guide Anatoli Boukreev's decision not to use bottled oxygen was sharply criticised by Jon Krakauer. Boukreev's supporters (who include G. Weston DeWalt, who co-wrote The Climb) state that using bottled oxygen gives a false sense of security. Krakauer and his supporters point out that, without bottled oxygen, Boukreev could not directly help his clients descend.

The low oxygen can cause a mental fog-like impairment of cognitive abilities described as "delayed and lethargic thought process, clinically defined as bradypsychia" even after returning to lower altitudes. In severe cases, climbers can experience hallucinations. Some studies have found that high-altitude climbers, including Everest climbers, experience altered brain structure.

Autumn climbing

Although generally less popular than spring, Mount Everest has also been climbed in the autumn (also called the "post-monsoon season"). For example, in 2010 Eric Larsen and five Nepali guides summited Everest in the autumn for the first time in ten years. The autumn season, when the monsoon ends, is regarded as more dangerous because there is typically a lot of new snow which can be unstable. However, this increased snow can make it more popular with certain winter sports like skiing and snowboarding. Two Japanese climbers also summited in October 1973.

Chris Chandler and Bob Cormack summited Everest in October 1976 as part of the American Bicentennial Everest Expedition that year, the first Americans to make an autumn ascent of Mount Everest according to the Los Angeles Times. By the 21st century, summer and autumn can be more popular with skiing and snowboard attempts on Mount Everest. During the 1980s, climbing in autumn was actually more popular than in spring. U.S. astronaut Karl Gordon Henize died in October 1993 on an autumn expedition, conducting an experiment on radiation. The amount of background radiation increases with higher altitudes.

The mountain has also been climbed in the winter, but that is not popular because of the combination of cold high winds and shorter days. By January the peak is typically battered by 270 km/h (170 mph) winds and the average temperature of the summit is around −33 °F (−36 °C).

Thefts and crime

Some climbers have reported life-threatening thefts from supply caches. In May 2006, Vitor Negrete, the first Brazilian to climb Everest without oxygen and part of David Sharp's party, died during his descent, and theft of gear and food from his high-altitude camp may have contributed. In addition to theft, Michael Kodas describes in his book, High Crimes: The Fate of Everest in an Age of Greed (2008): unethical guides and Sherpas, prostitution and gambling at the Tibet Base Camp, fraud related to the sale of oxygen bottles, and climbers collecting donations under the pretense of removing trash from the mountain.

The Chinese side of Everest in Tibet was described as "out of control" in 2007 after one Canadian had all his gear stolen and was abandoned by his Sherpa. Another Sherpa helped the victim get off the mountain safely and gave him some spare gear. Other climbers have also reported missing oxygen bottles, which can be worth hundreds of dollars each. Hundreds of climbers pass by people's tents, making it hard to safeguard against theft. In the late 2010s, the reports of theft of oxygen bottles from camps became more common.

Timeline

Main article: Timeline of climbing Mount Everest

See also: List of Mount Everest records

By the end of the 2010 climbing season, there had been 5,104 ascents to the summit by about 3,142 individuals. Some notable "firsts" by climbers include:

• 1922: First climb to 8,000 metres (26,247 ft), by George Mallory, Col. Felix Norton and Howard Somervell
• 1952: First climb to South Col by 1952 Swiss Mount Everest expedition
• 1953: First ascent, by Tenzing Norgay and Edmund Hillary on 1953 British Mount Everest expedition
• 1960: First reported ascent from the North Ridge by Wang Fuzhou, Gonpo and Qu Yinhua of China.
• 1975: First female ascent, by Junko Tabei (16 May).
• 1975: First female ascent from the North Ridge, by Phanthog, deputy head of the second Chinese Everest expedition that sent nine climbers to the summit (27 May).
• 1978: First ascent without supplemental oxygen by Reinhold Messner and Peter Habeler
• 1978: First solo ascent, by Franz Oppurg
• 1980: First winter ascent, by Polish National Expedition Winter 1979/1980 (Leszek Cichy and Krzysztof Wielicki)
• 1980: Second solo ascent, and the first without supplemental oxygen, by Reinhold Messner
• 1988: First "cross-over" climb by Chinese, Japanese and Nepali teams which ascended the peak simultaneously from both the North and South sides of the mountain and descended down the other side. The cross-over climb was also the first to be recorded on live broadcast television.
• 1988: First descent by paraglider, by Jean-Marc Boivin
• 1988: First female ascent without supplemental oxygen by Lydia Bradey
• 2000: Lhakpa Sherpa becomes first Nepali woman to summit Everest and survive.
• 2000: First descent by ski by Davo Karničar
• 2001: First descent by snowboard by Marco Siffredi
• 2001: First ascent by a blind climber, Erik Weihenmayer
• 2025: First descent by ski without supplemental oxygen by Andrzej Bargiel

Aviation

Main article: Houston–Mount Everest flight expedition

In 1933, a British woman named Lucy, Lady Houston paid for a group of airplanes to fly over Mount Everest. The planes were led by the Marquess of Clydesdale and tried to take pictures of the mountain.

In 1988, a climber named Jean-Marc Boivin reached the top of Everest and then flew down using a paraglider. This was the first time anyone had done this and it was also the fastest way anyone had ever come down from the mountain’s peak.

In 2005, a pilot from France named Didier Delsalle landed a small helicopter on the very top of Everest. He only meant to stay for two minutes to set a record, but he stayed a little longer. This was the highest any helicopter had ever landed or taken off from.

Extreme sports

Mount Everest is a popular destination for daring winter sports and adventures beyond traditional climbing. It has hosted activities such as snowboarding, skiing, paragliding, and gliding.

Notable achievements include Yuichiro Miura being the first person to ski down the mountain in the 1970s, and Stefan Gatt and Marco Siffredi snowboarding down its slopes in 2001. Other famous skiers include Davo Karničar from Slovenia, Hans Kammerlander from Italy, and Kit DesLauriers from the United States. In 2025, Andrzej Bargiel completed the first ski descent without using extra oxygen. Gliding descents have also grown in popularity, with Jean-Marc Boivin making the first paraglider descent from the Southeast Ridge in 1988, and Nepalis Sano Babu Sunuwar and Lakpa Tsheri Sherpa gliding down 5,000 metres in just 45 minutes in 2011.

Religious significance

Mount Everest holds deep spiritual meaning for many. The southern part of the mountain is thought to be a hidden valley of refuge, designated by Padmasambhava, a famous ninth-century Buddhist teacher.

Near the base on the north side lies Rongbuk Monastery, an important pilgrimage site for Sherpa people in the Khumbu region. The Sherpa believe that a Buddhist goddess named Miyolangsangma lives at the mountain's peak, making Everest her home. Climbers are seen as guests in this sacred place and should show respect.

Waste management

Further information: Impacts of tourism § Mount Everest

The high levels of pollution and waste on Mount Everest have become a big concern, especially human waste left by climbers. Each season, a large amount of waste is left on the mountain, making some areas very dirty. Climbers used to leave waste in the snow or near their tents, but now rules require them to bring a certain amount of waste back down with them.

Efforts to clean up Mount Everest continue, with campaigns to collect garbage and new rules to help protect the mountain. In 2019, China closed its base camp to visitors without permits, and local authorities are working to keep the area clean.