Mount Everest

The roof of the world. At 8849 meters, Mount Everest isn't just the highest point on Earth — it's the most extreme place a human being can reach on foot, a zone where the air delivers just 31% of the oxygen available at sea level. That's not a figure to skim past. At that pressure, the brain slows down, muscles burn acid with every single step, and fingers stiffen inside gloves even at −20°C inside the tent. Yet every May, during the narrow pre-monsoon window, hundreds of climbers from every continent push toward the Death Zone. Some make it.

Quick Facts

The Route (South Col)

The South Col Route — first climbed by Edmund Hillary and Tenzing Norgay on 29 May 1953 — is Everest's most-used line. It runs entirely on the Nepalese side (southeast ridge), from Base Camp to the summit via four progressive high camps.

Base Camp → Camp I: the Khumbu Icefall

5364 m → 6065 m | Elevation gain: +701 m | Time: 3–5h

The most objectively dangerous section of the entire route. The Khumbu Icefall is a moving glacier — ice blocks the size of buildings shift, crack, and collapse without warning. Every morning, Sherpa teams (the Icefall Doctors) reposition aluminum ladders and fixed ropes across the crevasses. You cross at night or at dawn, when cold slows the ice's movement. There's no such thing as safe here — seracs and avalanches have killed more climbers in the Icefall than anywhere else on the mountain.

Camp I → Camp II: the Western Cwm

6065 m → 6400 m | Elevation gain: +335 m | Time: 2–4h

Past the Icefall, the Western Cwm opens up — a nearly flat glacial plateau enclosed by the walls of Everest, Lhotse, and Nuptse. Sun reflecting off white snow burns through double-lens glacier glasses. Wind is almost absent. Temperatures can climb above +30°C at midday. Surreal for 6400 meters.

Camp II → Camp III: the Lhotse Face

6400 m → 7200 m | Elevation gain: +800 m | Time: 4–6h

The technical heart of the route. The Lhotse Face is 800 meters of 45–50° ice equipped with fixed ropes throughout the season. You ascend with crampons and jumars. Camp III clings to a narrow ice ledge — tents barely fit. Sleeping here is unsettling: the body is already consuming itself overnight, oxygen is scarce, sleep is fragmented. At 7200 m, you're breathing air with 40% of the oxygen available at sea level.

Camp III → Camp IV (South Col)

7200 m → 7920 m | Elevation gain: +720 m | Time: 4–6h

You cross the Yellow Band — a band of pale limestone, the remnant of an ancient seabed pushed skyward by plate tectonics — and then the Geneva Spur, a black rock buttress requiring mixed climbing. Then the desolate plateau of the South Col (7920 m): shredded tents from past expeditions, empty oxygen cylinders, temperatures down to −40°C, wind gusting past 100 km/h. This is your high camp before the final push.

Camp IV → Summit: the Longest Night

7920 m → 8849 m | Elevation gain: +929 m | Time: 7–12h

Departure: between midnight and 2 AM, headlamp on, cold biting through every layer. You climb the Triangle Face of hard snow to the Balcony (8400 m) — a flat platform where you check your oxygen cylinders. Then the southeast ridge, exposed on both sides, toward the South Summit (8748 m). From there you drop slightly onto a knife-edge snow ridge, cross the Hillary Step (a mixed rock-and-snow section, significantly reshaped by the 2015 earthquake), and traverse the final exposed ridge. Then the summit: a triangular platform big enough for three, maybe four people. The oxygen is 31% of what you'd breathe at sea level. Clear thinking is hard work.

Oxygen and Acclimatization

At 8849 m, barometric pressure drops to approximately 314 hPa — about 31% of sea-level pressure (1013 hPa). The oxygen available is 31%. Enough to sustain life for short periods. Not enough to function normally.

Typical summit SpO₂ ranges between 54 and 70% for well-acclimatized climbers using supplemental oxygen at 1–4 L/min. Without supplemental oxygen, values drop sharply: the landmark study by Grocott et al. (NEJM, 2009) recorded mean summit SpO₂ of 54%, with some climbers dropping below 40%. About 5% of summiteers climb without oxygen — an extreme risk reserved for elite athletes with years of specific adaptation.

The Death Zone starts at 8000 m. Above that line, the body no longer acclimatizes. It deteriorates. The goal is to spend as little time there as possible.

Standard acclimatization follows 3–4 rotations through April and early May, always applying the climb high, sleep low principle:

1. Base Camp → Camp II → return to BC (first rotation)
2. Base Camp → Camp III → return to BC (second rotation)
3. Base Camp → Camp IV → summit attempt → full descent

Between rotations, climbers return to Base Camp or lower (Lobuche, Pheriche) to recover. The body builds red blood cells, increases mitochondrial density, and improves respiratory efficiency — but it needs weeks, not days.

Extreme AMS at this altitude presents as: shattering headache, vomiting, mental confusion, hallucinations (documented in dozens of expedition diaries), and inability to coordinate movement. At extreme altitude it's hard to distinguish exhaustion from HACE (High Altitude Cerebral Edema). The response is always the same: descend immediately.

Note: This information is educational and does not replace medical advice. Consult a physician specializing in altitude medicine before attempting Everest.

Preparation

Physically, Everest demands years of progressive preparation. You don't arrive at Everest without first having climbed at least one Himalayan peak above 7000 m — Mera Peak, Island Peak, Ama Dablam, or Cho Oyu are common stepping stones. Minimum recommended VO₂max: ≥ 60 ml/kg/min. Training must include extended high-altitude outings, steep carries with a heavy pack, and sustained aerobic sessions.

Technically, the South Col Route requires: crampon technique on 45–50° ice, jumar use on fixed ropes, mixed climbing (rock + ice) while wearing an oxygen mask, and ridge navigation in low visibility.

Essential gear:

• Oxygen mask and regulator (Poisk or TopOut system, expedition standard)
• Oxygen cylinders (minimum 3–4 × 6L for the summit push)
• High-altitude down suit (rated to −40°C)
• Double mountaineering boots
• 12-point rigid crampons
• Technical ice axe
• Jumar and descender
• VHF radio

Cost of a standard South Col expedition: $40,000–$80,000 USD, including Nepal climbing permit (~$11,000 per climber), Sherpa team, oxygen, Base Camp cook, and insurance.

The Most Overcrowded Mountain on Earth

On 22 May 2019, Nirmal Purja took a photograph from the northeast ridge. It became the defining image of an unprecedented problem: a queue of climbers packed like a highway traffic jam on the Hillary Step, hundreds of people waiting motionless in the Death Zone. Eleven climbers died that week — some deaths directly attributed to the prolonged wait above 8,000 metres.

The numbers. In the 2023 season, Nepal issued more than 470 permits at approximately $11,000 each. Counting Sherpas, high-altitude porters, and support staff, an estimated 4,000–6,000 people are on the Nepalese side simultaneously during May. The South Col Route — opened by three people in 1953 — has become a seasonal highway.

Waste and contamination. Since 1953, an estimated 50+ tonnes of material have been abandoned on the mountain: spent oxygen cylinders, tents, ropes, food, human waste. Extreme cold slows decomposition — rubbish emerges intact from the ice decades later. Nepal has mandated that each climber must carry down at least 8 kg of waste (beyond their own gear), backed by cash deposits. The 2023 cleanup expedition removed roughly 11 tonnes — and the mountain is still dirty.

The bodies. More than 310 people have died on Everest since 1924. Many bodies have never been recovered: rescue in the Death Zone is dangerous and often impossible, and the remains lie frozen in the mountain. Climate change and glacier melt are now surfacing bodies buried for decades.

The economics. Permits generate more than $5 million per season for Nepal. Limiting numbers means cutting revenue that the Himalayan tourism economy has been built on for thirty years. The quota debate exists — and closes every time someone looks at the bank balance.

For those heading up today, awareness is part of the mountaineering ethic: choose operators who respect cleanup protocols, verify that guides and Sherpa porters are paid fairly, carry every piece of rubbish back down. The mountain you carry home isn't only in your legs — it's in the responsibility of having passed through it.

Frequently Asked Questions

How much oxygen is there at the summit of Everest?

At the summit of Everest, at 8849 m, the available oxygen is 31% of what you'd breathe at sea level. Barometric pressure drops to around 314 hPa (versus 1013 hPa at sea level). Nearly all climbers use supplemental oxygen during the summit push — the exceptions are counted in single digits each season.

How many days does it take to climb Everest?

A complete expedition typically requires 55–70 days total: acclimatization in Kathmandu, trek to Base Camp (10–14 days), three or four high-camp rotations throughout April, then the summit attempt during the May window. There's no shortcut. The body needs time.

What is the death rate on Everest?

The historical mortality rate on Everest stands around 1–1.5% per summit attempt in recent seasons — lower than historical averages thanks to improved weather forecasting, more reliable oxygen systems, and better-organized rescue teams. Leading causes of death: avalanches and serac collapse, falls on technical terrain, cerebral and pulmonary edema, hypothermia.

Do you need supplemental oxygen to climb Everest?

Technically no — about 5% of summiteers reach the top without it. But it's an enormous risk. The vast majority use supplemental oxygen above 7000–7500 m for sleeping and climbing, at flow rates of 1–4 L/min. Without oxygen, the probability of fatal judgment errors increases dramatically, and mortality statistics reflect that clearly.

Want to calculate available oxygen at any point along the route? Use the free altitude oxygen calculator for barometric pressure and SpO₂ data at any elevation.