How Climbing Mount Everest Works

By: Hannah Harris
Mount Everest as seen from the nearby mountain of Kala Patthar. See more pictures of Mount Everest.
2008 HowStuffWorks

Mount Everest is literally located at the top of the world, rising 29,035 feet (8850 meters) above sea level. As soon as it was crowned the world's tallest mountain, people inevitably had to climb it. And just as inevitably, many of them failed. While more than 2,200 people have succeeded, nearly 200 have lost their lives attempting the climb.

So why climb Everest? The most famous answer to this question came from climber George Mallory: "because it is there." Though he was likely responding in frustration after being asked the same question dozens of times, his answer succinctly cuts to the heart of the matter.


In this article, we'll examine the history of climbing Mount Everest, see what routes most climbers use and find out what climbers take with them to survive the trek.

Everest hasn't always been considered the king of mountains. It wasn't until 1852 that a Bengali mathematician and surveyor named Radhanath Sikhdar determined that "Peak XV" was actually the highest point on the earth. In 1865, Sikhdar's discovery was confirmed. India's Surveyor General Sir Andrew Waugh renamed the mountain Mount Everest after Sir George Everest, the previous Surveyor General and the person overseeing the original survey that listed "Peak XV."

The Nepalese who live to the south of Mount Everest have always known that it was special. They called it Sagarmatha, which is translated variously as "goddess of the sky" and "forehead of the sky." The Tibetans living north of the mountain called it Chomolungma, or "mother goddess of the world."

Politics kept would-be climbers out of Everest for many years following its discovery, because neither the Nepalese nor Tibetan governments welcomed strangers into their countries. But in 1921, after much diplomatic negotiation, Tibet opened its borders and the first of many British expeditions began on the mountain's north side.

Take a look at the next page to learn about the first expeditions to explore Mount Everest.



Everest Expeditions

One of the first Everest expeditions included British nationals George Leigh Mallory and Andrew Irvine. Their 1924 expedition was Mallory's third trip to the mountain. In a 1922 attempt, climbers reached record altitudes before deteriorating weather conditions forced them to turn back. During that attempt, an avalanche killed seven Sherpas.

On the morning of June 8th 1924, Mallory and Irvine left the highest camp on Everest bound for the summit. At 1 p.m. they were seen climbing the mountain, behind schedule but still making progress towards the top. After that, they were never seen again. In 1999, a team of investigators located Mallory's body on the north face of Everest around 27,000 feet. There is some debate over whether Mallory and Irvine made it to the top, but most believe that they did not.


In 1949, the political situation around Everest reversed and Nepal opened its borders, one year before the Chinese government closed Tibet. Climbers shifted their approach to the south and in 1953, someone finally made it to the top. Edmund Hillary, a New Zealand mountain climber and beekeeper, and Tenzing Norgay, a Sherpa, are the first people credited with reaching the Mountain's summit. Theirs would be the first of many notable firsts on Everest:

  • In 1963, James Whittaker became the first American to reach the summit of Everest.
  • In 1975, a Japanese woman named Junko Tabei became the first woman to summit.
  • In a truly incredible first, American Erik Weihenmayer became the first blind person to scale Everest in 2001. Click here to read more about his amazing journey.

Next, we'll look at all of the gear that Everest climbers take with them to understand what it takes to get to the top.


Gear and Supplies

These high-altitude double boots have an inner and outer boot and gaiters.
Image courtesy HowStuffWorks Shopper

Mount Everest climbers need a lot of specialized gear, including clothing, tools and supplies. This list is by no means comprehensive, but can give you an idea of the amount of equipment required. If you're going on a guided expedition, you should carefully check to see what they'll provide. You should also test all of your gear before the trip. Alpine Ascents and have detailed lists of necessities and brand suggestions.


Climbers need several pairs of socks, including trekking, wool and liner socks. They also need lightweight hiking boots as well as plastic, lined climbing boots. These should be large to give feet more room and reduce the risk of frostbite. Heating pads and wires are available to help keep boots warm, and depending on the type of boot, you may also need insulated overboots. Gaiters are included on some boots; otherwise you will need them to help keep your feet warm and dry.



Layering is important in choosing clothing. There is a great deal of variation in temperature between camps, depending on the weather and time of day, so you will need both lightweight and expedition-weight underwear. You'll also need a fleece or synthetic zip-up jacket, an expedition-weight down parka and a Gore-Tex shell jacket with a hood. Synthetic insulated pants, down pants and a pair of Gore-Tex shell pants (all windproof with full-separating side-zippers) are required.

A heavyweight balaclava
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For your head, you'll need a headlamp with spare bulbs and batteries; glacier glasses with side covers; ski goggles; a baseball cap or visor; a wool hat and both lightweight and heavyweight balaclavas. Synthetic bandanas will protect your neck. You'll also need a total of four different pairs of gloves: light synthetic ones that can fit inside the others, expedition-weight fleece gloves, waterproof gloves and expedition-weight mitts.

Climbing Tools

Clipped to your boots are step-in glacier crampons. Climbers should bring spares in case these are damaged. You also need an alpine climbing harness that will fit over all of your clothes, three locking and three stationary carabiners, one right and one left ascender, a belay device, and prussiks (or 40 feet of flexible six milimeter perlon rope to make into prussiks). An ice ax with a leash designed for glacier axes is required to cross the Lhotse Face and climb to the summit. The length should be determined by your height -- if you're under 5 feet 7 inches tall, your ax should be 60 centimeters long (about 24 inches); people from 5 feet 7 inches to 6 feet 1 inch tall need an ax that's 65 centimeters (about 26 inches) long. You'll also need glacier rope. Check out Get Outdoors' Glacier Travel: Fundamentals for details on "roping up" and glacier rope travel.

Carabiners and a belay device

Camp Supplies

Two good-quality down sleeping bags (expedition-quality and rated to at least 20 C and 40 C below zero) as well as at least two self-inflating pads and one thermal pad per camp to go under them is necessary; at some camps you may be better off doubling the pads.

A few of the many tools and supplies needed to climb Everest.
Image courtesy HowStuffWorks Shopper

You will also need multiple tents: a larger tent for Base Camp and smaller, lighter, high-quality tents for higher elevations. A GPS unit will help you find the summit. Bringing two titanium burners will ensure that at least one works when you need it (and allows you to cook faster). For cooking and eating, you need two or three light pots with lids, plastic mugs, a thermos, a spoon and knife (like a Leatherman), and a couple of potholders.

Lots of matches and lighters are necessary for heating and cooking; make sure the latter are of good quality so they will work at high altitude. Bringing a chemical water purifier will reduce the amount of water that you need to boil, and consequently the amount of fuel required.

You will need two plastic water bottles in addition to a wide mouthed bottle for urination. The trekking agency may supply gas and oxygen if applicable. Large duffel bags are necessary for transporting your gear and so is a backpack for carrying it (you may want an extra, small backpack for treks). The climbing pack will need attachment points for your ax and other climbing gear. Sunscreen, lip balm and a small personal first aid kit should all fit in your pack.

Electronic Equipment

Cameras are essential, and walkie-talkies might be a good idea. Lithium batteries are best for long life and function at high altitudes. Increasing numbers of climbers are bringing other electronic equipment such as laptops, video cameras and satellite phones.

Even if you've got all your equipment, you'll probably need some expert help to climb 30,000 feet. And how much will it all cost, anyway? Find out on the next page.


Guided Everest Tours

Image courtesy Alan Arnette

Beginning in the 1990s, experienced climbers like Rob Hall began organizing group tours, which made Everest accessible for the first time to less experienced people. Guided tours will involve an expedition leader, other guides and a Sherpa support team. There are pros and cons to joining a guided tour, but if you are considering it, experts recommend that you climb another, less difficult mountain with them first.

Even "solo" climbers often hire Sherpas to assist with the climb, and hiring a cook for Camp II can greatly improve the quality of your experience.



The average cost of a fully guided journey up Everest from the south side is $65,000. A fully guided climb from the north costs somewhat less, averaging around $40,000. These costs do not typically include personal gear, international laptop and digital camera.


The Ascent

The two most common routes up Everest: the South Col and the North Col-North Ridge
Image courtesy NASA

Most climbers attempt Everest during April and May. In the winter, low temperat­ures and hurricane force winds make climbing difficult. Between June and September, summer monsoons create intense storms and violent precipitation.

From home and back again, most trips to the top over Everest take about two and a half months. For a southern approach, climbers typically fly into Katmandu and spend several days there buying supplies and arranging travel visas. From Katmandu, they fly to Lukla and make their way overland to Base Camp, where they prepare for their Everest climb. Even the Base Camp is located at high altitude, so the journey there must progress gradually, usually taking one to two weeks.


The South Col Route was taken by Sir Edmund Hillary and Tenzing Norgay and is still the route used most frequently. It goes through the treacherous Khumbu Icefall and Western Cwm (pronounced "coom"), up the Lhotse Face and past the South Col and Hillary Step to the summit.

The North Ridge Route is the second-most popular route. It's a more difficult climb technically and requires a longer descent at high altitude than the Southern Route, though it avoids the dangers of the Khumbu Icefall. In total, there are 15 different routes and route variations to the top of Everest.

Ascending from the south, climbers make use of five different camps as they adjust to high altitude. Base Camp is located at 17,600 feet (5364 m). Temperatures tend to be about 1.5 degrees C warmer than the summit per 150 meters of altitude drop and range between 17 C below zero in January to 3 C below in the summer. During the spring climbing season Base Camp houses about 300 people, including climbers, Sherpas, doctors, scientists and other support staff.

Base Camp with the Khumbu Icefall in the background.
Image courtesy Sheila Kavanagh, Seven Summits
The Khumbu Icefall
Image courtesy Alan Arnette

From Base Camp, climbers must pass through the Khumbu Icefall. They can only traverse this area with the aid of ropes and ladders. Even with all the safety precautions, this section is extremely dangerous. Shifting ice, deep crevasses, falling ice and avalanches have killed many climbers and Sherpas there. Once through the Khumbu Icefall, climbers reach Camp I at 19,900 feet (6065 m). Most climbers must navigate the Khumbu Icefall multiple times as they acclimate to the elevation.

Climbers using ropes and ladders to traverse the Khumbu Icefall.
Image courtesy Alan Arnette

Travel from Camp I to Camp II at 21,300 feet (6492 m) takes climbers through the glacial valley known as the Western Cwm. Surprisingly, the main challenge in the Western Cwm is heat. The valley's structure means there is little wind and the intense sunlight at such a high altitude can make it uncomfortably hot.

Camp I in the Western Cwm
Image courtesy Alan Arnette

The next challenge is climbing Lhotse Face using fixed ropes to get across a sheer wall of ice and ascend to Camp III at 24,500 ft (7470 m). Climbers must also use ropes to get across the Geneva Spur to reach Camp IV.

The Lhotse Face
Image courtesy Alan Arnette

Camp IV, also known as the South Col ("Col" is a word for saddle, or pass) is the last major camp before climbers make their summit push. Located at 26,000 ft (7925 m) it is the first night most climbers spend in the Death Zone.

Everest's South Summit
Image courtesy Alan Arnette

From Camp IV, climbers hike to The Balcony, at 27,700 ft (8440 m). The Balcony provides a platform where climbers can rest. From there they proceed to The Cornice Traverse, a horizontal face of snow and rock that must be climbed, and finally onto The Hillary Step which is climbed with fixed ropes, so that only one climber can ascend or descend at a time. At this point, the lack of oxygen and cold dulls climbers' reflexes and judgment, making the Hillary Step one of the most challenging elements of the climb.

Everest's North Summit
Image courtesy Michael Otis

From the Hillary Step, climbers must trek the final feet to reach the summit. Near the top are survey and scientific equipment, prayer flags, discarded oxygen bottles, and a few other small items and mementoes left by climbers. From the summit, you can see across the Tibetan Plateau, towards the other Himalayan peaks of Cho Oyu, Makalu and Kanchenjunga. Most climbers stop to take some pictures and enjoy the 360 degree view before heading down again. As the list of deaths attests, getting down safely can be at least as dangerous as getting up.

Tibet as seen from the North Summit
Image courtesy Michael Otis

Most climbers require about four days to ascend Mount Everest from Base Camp. The fastest ascent from the north side is held by Hans Kammerlander of Italy and took him 16 hours and 45 minutes from Base Camp. The fastest ascent from the South took just under 11 hours and was accomplished by Lakba Gelu Sherpa. Babu Chiri Sherpa, who was at the summit for 21.5 hours, holds the record for the most time spent on top of Everest. However, people typically spend about an hour at the top on average.

If you’d like to climb an icy peak but aren’t experienced enough to do it, you can always practice in an indoor ice climbing facility.

Next, we'll look at the effect that climbing Mount Everest has on the region and on climbers themselves.


Ecological Impact on Mount Everest

Mount Everest at sunset
Image courtesy US Geological Survey

Following the successful summit in 1953, more and more climbers began to come to Everest, intent on emulating the first climbers. This flood of visitors brought an influx of cash as well as infrastructure to Sherpa communities. There are now schools, hospitals, and stores selling Western goods and food. With the visitors came increased deforestation for firewood, as well as a great deal of litter.

Like most alpine areas, the Himalayas are ecologically fragile. Hundreds of climbers travel to the area each year in the hopes of summiting Everest, but an additional 25,000 Everest tourists visit the area as well. Today, climbers, locals and the Nepalese government are all working to protect the environment around Everest.


In 1976, Everest and the surrounding area were designated as Sagarmatha National Park. In 1979, the area was made a Natural World Heritage Site. Currently, flora and fauna in the park are protected and the collection of firewood is prohibited.

In 1998, a private team calling itself the Everest Environmental Expedition removed 1.2 tons of waste from Everest, collected primarily around Base Camp and Camp II. While plastic bottles and empty oxygen canisters are unsightly, batteries, spent fuel cylinders, and human waste actually pose a greater environmental risk and the expedition focused its efforts on these types of litter. Other environmental expeditions continue the effort to clean up Everest.

The Nepalese government now requires a $4,000 deposit from climbers that it refunds only if they bring down the same amount of gear and supplies that they took up.


Physical Effects of Climbing Mount Everest

Everest is an extremely inhospitable place. Temperatures at the top are typically around 36 degrees C below zero in the winter and can drop as low as 60 degrees C below. Temperatures only rise to an average of 18 below during the warmest part of the summer and monsoon storms make Everest insurmountable during this period. The jet stream buffets the top of Everest with hurricane force winds for much of the year. During April and May, the jet stream shifts somewhat, offering relatively calm weather and this is when most climbs occur.

Avalanches are a constant threat and they have claimed many lives. Fierce storms may blow up unexpectedly, trapping or blinding climbers. Shifting glaciers can open suddenly, creating deep crevasses, often obscured by snow.


Lack of oxygen is one of the major challenges posed by Everest. The oxygen levels at the top are only a third of what they are at sea level. Humans cannot survive for any length of time at elevation above 26,000 feet (8000 m), which on Everest is known as the "death zone." At this altitude, the human body is unable to acclimate to the low oxygen and begins to deteriorate. Most climbers must use oxygen and will have difficulty sleeping.

Even at moderate elevations, many people experience headaches and shortness of breath. However, if they stay at that elevation, the body will compensate by producing more red blood cells and all functions will return to normal. At higher elevations, these symptoms are extreme and may also include loss of appetite, nausea, vomiting, dizziness, irritability and insomnia.

When oxygen is severely limited, the body will compensate by increasing blood flow to the brain. At extremely high elevations, the brain can actually swell and blood vessels begin to leak, resulting in High Altitude Cerebral Edema, or HACE. When this happens, the climber may experience disorientation, hallucinations and even loss of consciousness. Similarly, High Altitude Pulmonary Edema, or HAPE, occurs when fluid accumulates in the lungs. This produces shortness of breath and chest tightness as well as coughing and bloody sputum.

Both HACE and HAPE are potentially life-threatening conditions. Descent is the best treatment and may require helicopter evacuation, as many patients are unable to descend on their own at that point. If descent is not possible, high altitude sickness is sometimes treated with Diamox, a drug that signals the brain to breathe more, or with dexamethasone, a steroid that may temporarily reduce swelling. If available, the patient can be placed in a Gamow bag, which is a portable high-pressure bag that increases oxygen tension and may stabilize the patient.

Or course, it is much better to avoid altitude sickness than to have to treat it. This is why Everest climbers typically make several trips up and down the mountain to increasingly high elevation camps to acclimate their bodies to high altitude conditions.

Other risks to Everest climbers include frostbite and sunburn, and broken bones from falls. Often, a combination of natural forces and human physiology produces lethal consequences for Everest mountaineers.


Training to Climb Mount Everest

A Sherpa memorial cairn with prayer flags.
Image courtesy Sheila Kavanagh, Seven Summits

Prospective Everest climbers train in a variety of ways. Swimming, running, weight loss on Everest, most prospective climbers try to gain a little weight before their trip.

Although Everest does not require the technical climbing skills of some shorter mountains, a thorough grounding in climbing techniques is important before attempting it. Because of the extreme conditions and unpredictable nature of Everest, even the most experienced mountaineers can get into trouble.


Today, more people than ever are attempting to climb Mount Everest, but only about one in four will succeed. There are an estimated 120 bodies still on Everest; while many have been respectfully relocated, it is too difficult and dangerous to attempt to remove all of them.

Given the expense, the risk, and discomfort, why do people climb Everest? In the early 20th century, when George Mallory was planning his expedition, explorers had reached both the North Pole and South Pole and there was a passion for new frontiers. Everest, the so-called "third pole," represented a new and interesting challenge.

Although more people are climbing Everest, neither modern equipment nor professional expertise can eliminate the challenge or the inherent difficulties. Paying for a fully guided trip does not guarantee success, nor does extensive experience eliminate risk. Climbing Mount Everest remains, to this day, a daunting and formidable challenge as climbers continue to push the envelope of human endurance and strength of will.


Lots More Information

Related Articles

More Great Links

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  • Eric Weihenmayer: No Boundaries, HowStuffWorks Express
  • "Everest 50." National Geographic Society, 2003.
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