Worst mountaineering disaster
Peak Lenin Avalanche
43 people
Kyrgyzstan ()

The deadliest mountaineering disaster occurred at Lenin Peak (today also known as Avicenna Peak) on the border between the Kyrgyz and Tajik SSRs (present-day Kyrgyzstan and Tajikistan) on 13 July 1990. At 9:30 p.m. local time, a minor earthquake dislodged a serac (a building-sized column of glacial ice) from the slopes of neighbouring Chapaev Peak, which collapsed on to the second basecamp on the Razdelnaya Route to the summit of Lenin Peak. Of the 45 mountaineers in the camp at the time, 43 died. The only survivors were mountaineer Alexei Koren (Russia) and climber Miro Grozman (Slovakia), the two men escaped with a broken arm and leg respectively.

After the avalanche, Grozman and Koren descended from the 5,300-m-high (17,388-ft) camp in their sleeping clothes looking for help. There was an extensive search-and-rescue operation in the weeks that followed the disaster, with the Soviet government sending helicopters and other equipment to aid the seach, but no other survivors were found. Only four bodies were recovered, with the rest buried beneath a concrete-hard layer of glacial ice. It was only in 2008 that remains began to emerge from the shrinking glacier. The climbers at Camp II that night were mostly from the Soviet Union, including 23 from the Leningrad Mountaineering Club. An additional 13 were from elsewhere in the world, including a six-person group from Czechoslovakia and four from Israel.

Peak Lenin is a 7,134-m (23,406-ft) summit in the norther Pamir Mountains. The most common routes to the summit approach from the North, or Kyrgyz side of the mountain. Although generally considered to be a relatively easy non-technical climb, Avicenna Peak has seen several tragedies over the years. Around 16 years before, in 1974, an eight-woman team died of exposure when they were caught in a storm during their descent.

The 2014 Nepal snowstorm disaster, sometimes referred to as the 2014 Annapurna Circuit Snowstorm, resulted in the cumulative deaths of 40 individuals belonging to multiple climbing parties. Several hundred trekkers, predominantly in the Manang and Mustang Districts of Nepal, were imperiled when cyclone Hudhud dumped almost 1.8 m (6 ft) of snow within 12 hours in the region. The massive snowfall and subsequent avalanches disrupted electrical power and phone connections, further hampering rescue efforts. About 400 climbers were successfully rescued in the days following the cyclone.

The next largest disaster affecting a single mountaineering expedition was near Mt Everest killing 26, 13 of whom were Japanese. A huge avalanche, triggered by a six foot snowfall due to a cyclone in the Bay of Bengal, stuck their overnight camp at 1.am.