People die on Mount Everest primarily from trauma (avalanches, falls, and icefall collapses) and from the mountain’s extreme environment slowly shutting their bodies down through altitude sickness, hypothermia, and oxygen deprivation. Of 192 deaths recorded above base camp between 1921 and 2006, 113 were traumatic, 52 were non-traumatic (altitude illness, hypothermia, or sudden cardiac events), and 27 were disappearances where the body was never found. The reality is that multiple factors often overlap: a climber weakened by thin air stumbles on a fixed line, or someone delayed by a crowd at high altitude runs out of supplemental oxygen and freezes.
The Death Zone Above 26,000 Feet
The single biggest factor in Everest fatalities is the altitude itself. Above roughly 26,000 feet (8,000 meters), the air holds so little oxygen that the human body cannot sustain itself indefinitely. Researchers from the Xtreme Everest project found that climbers on the summit often function with blood oxygen levels around 60 percent, a number that would trigger emergency alarms in any hospital. At sea level, a healthy person sits near 95 to 100 percent.
At these heights, your body is on a countdown. Major organs begin to fail from oxygen deprivation, and climbers are advised to spend no more than 48 hours in the death zone. Every minute spent waiting in line, resting, or moving slowly eats into that narrow window of survival. Most of Everest’s 300-plus deaths have occurred in this zone, where the margin between a successful summit and a fatal collapse is razor thin.
How Altitude Sickness Kills
Altitude sickness exists on a spectrum. Mild forms cause headache, nausea, and fatigue. The lethal forms are high-altitude cerebral edema (HACE) and high-altitude pulmonary edema (HAPE), both caused by the body’s response to extremely low oxygen.
In HACE, the blood vessels in the brain dilate and begin leaking fluid. The brain swells, pressure inside the skull rises, and the climber develops confusion, loss of coordination, and eventually coma. Without descent or treatment, death from brain herniation can follow within 12 to 24 hours. HAPE works similarly but in the lungs: fluid leaks into the air sacs, making it progressively harder to breathe, essentially drowning a person from the inside.
These two conditions frequently overlap. Studies show that 13 to 20 percent of climbers who develop HAPE also have HACE, and autopsies of people who died from HAPE reveal signs of brain swelling in about half of cases. The challenge on Everest is that both conditions strike in the death zone, where evacuation is nearly impossible and the only real treatment, getting to lower altitude, requires energy the climber may no longer have.
Avalanches, Falls, and Icefall
Trauma is the leading category of death on Everest. The largest single class involves “objective hazards,” meaning dangers the climber can’t control: avalanches, collapsing ice towers called seracs, crevasses opening beneath their feet, and rockfall. Between 1921 and 2006, 67 people died from these hazards alone, and Sherpa workers bore the worst of it, accounting for 47 of those deaths.
The Khumbu Icefall, a constantly shifting glacier at around 19,000 feet that every climber on the standard route must pass through multiple times, is considered one of the most dangerous places in mountaineering. In 2014, an avalanche swept through the icefall and killed 16 Sherpas in a single event, making it the deadliest day in the mountain’s history at that time. Climbers and guides sometimes watch avalanches pour directly over the climbing route from the safety of base camp. The icefall moves and cracks daily, and the aluminum ladders bridging its crevasses can shift overnight.
Falls account for another 46 deaths in the historical record. These happen on steep, icy terrain where exhaustion, hypoxia, or a moment of lost coordination sends a climber off a ridge or down a slope.
Extreme Cold and Wind
Even during the climbing season in May, the summit averages around minus 26°C (minus 15°F) with winds of about 36 miles per hour. Factor in wind chill and the effective temperature drops to roughly minus 45°C (minus 49°F). At that wind chill, exposed skin can develop frostbite in about six to seven minutes.
In winter, conditions become almost incomprehensible. Average wind chill on the summit reaches minus 65°C (minus 85°F), and frostbite on exposed skin begins in under one minute. The most extreme temperatures recorded on the summit have plunged to minus 49°C, with winds reaching 180 miles per hour.
Hypothermia killed at least 11 climbers in the historical record, though the real number is almost certainly higher. Many of the 27 people classified as “disappeared” likely succumbed to cold and wind before being buried by snow or falling from exposed ridges. A climber who runs out of supplemental oxygen at high altitude loses not only the ability to think clearly but also the body heat generated by adequate metabolism. Sitting down to rest in the death zone is often the last decision a person makes.
Crowding and Oxygen Supply
In 2023, Nepal issued a record 478 climbing permits, and 18 climbers died that season. Overcrowding was cited as a major contributing factor. On summit day, hundreds of climbers may attempt to pass through the same narrow sections of the route, creating bottlenecks where people stand in line for hours at extreme altitude.
Those delays are dangerous because climbers carry a finite supply of supplemental oxygen, typically calculated for a specific pace and turnaround time. An unexpected two-hour wait in a queue at 28,000 feet can mean running out of oxygen on the descent, which is when most deaths occur. Oxygen regulators have also historically been unreliable, and a mechanical failure at high altitude can be fatal even if the bottles themselves are full. The weight of the oxygen system, which in earlier decades exceeded 30 pounds, adds to exhaustion and slows movement further.
Why Sherpas Face Different Risks
About one-third of all Everest deaths have been Sherpas. Of roughly 290 total fatalities recorded by the Himalayan Database, 94 were Sherpa workers. Their risk profile looks different from that of foreign climbers. While a commercial client is statistically more likely to die near the summit, a Sherpa is more likely to die in the Khumbu Icefall, where they make repeated trips to establish camps and fix ropes.
Sherpas carry heavy loads through the icefall dozens of times per season, multiplying their exposure to avalanche and serac collapse. The 2014 icefall disaster and a 2015 earthquake that killed at least 17 people at base camp (including seven Sherpas) highlight how the mountain’s deadliest moments often hit the workforce hardest.
Why Bodies Stay on the Mountain
More than 200 bodies remain on Everest, most of them in the death zone. Retrieving a body requires six to ten Sherpas working for most of a day, at extreme personal risk, and costs between $30,000 and $70,000. A frozen body that weighed 80 kilograms in life can weigh 150 kilograms when encased in ice. Helicopters generally cannot land above Camp 2 at 21,000 feet because the air is too thin to generate sufficient lift. Recovery attempts have themselves resulted in deaths, which is why many families ultimately choose to leave their loved ones on the mountain.