Louis Lachenal, born July 17, 1921 in Annecy and died November 25, 1955 in the Vallée Blanche in Chamonix, is a French mountaineer, first winner with Maurice Herzog, in 1950, of one of the peaks over eight thousand meters: Annapurna (8091 meters).

Louis Lachenal made his first ascents on the Biclope rock in 1934. An assiduous choir boy, he preferred the world of the street to school benches. His taste for risk and the search for danger will be for him a sort of ideal of life. Thus, at the age of 13, his vocation called him to the mountains surrounding Annecy: La Tournette, Parmelan, Arcalod. In 1941, he became a member of the organization Jeunesse et Montagne. In 1942, he became a certified member of the Club Alpin Français. In June-July he took part in a mountaineering course from which he graduated as first roper and met Lionel Terray. Later, he meets Gaston Rébuffat, by chance, in a stationary train. On October 1, he was hired as a mountaineering and ski instructor at the Contamines-Montjoie center. On November 12, 1942, he married Adèle Rivier (1920-1983). From this union were born two sons, Jean-Claude (1944) and Christian (1946).

In 1945, he made his first races with Lionel Terray: the north face of Les Droites and the east face of Le Moine. He followed, among other things, and always in the company of Lionel Terray, the fourth ascent of the Walker spur in 1946, the second ascent of the Eigerwand wall in 19472. In 1948, he became a member of the Compagnie des Guides de Chamonix . In 1949, he chained the ascents. In particular, he undertakes to climb three reputedly difficult routes in a single day (east ridge of the Crocodile, east face of the Caiman, Ryan route in Plan).

On June 3, 1950, he was part of the agreement with Maurice Herzog who reached the summit of Annapurna, the first in the world to reach a summit of more than eight thousand meters. Both men did not have oxygen masks. This victory over Annapurna is also that of a team: Gaston Rébuffat, Lionel Terray, Jean Couzy, Marcel Schatz, Dr. Jacques Oudot and filmmaker Marcel Ichac (the only one who already has experience in the Himalayas). During this expedition, Lachenal's feet froze and had to be amputated. The descent resembles a long Stations of the Cross that lasts more than a month, from June 4 to July 7.

After his return to Orly airport, a stay at the Vaugirard clinic and the presentation of the Legion of Honor, Louis Lachenal returned to Chamonix. He then gave a series of lectures (Knowledge of the world), starting in 1951. He began to drive cars before resuming training and climbing. He took over the management of the French alpine skiing and slalom team and climbed Mount Rose in August 1955.

On the afternoon of November 25, 1955, he took Jean-Pierre Payot skiing in the Vallée Blanche, above Chamonix. Skiing ahead of him at high speed, he suddenly disappeared into a crevasse hidden by a snow bridge, which Payot narrowly avoided. With great difficulty, he managed to warn the Chamonix guides who, during the night, recovered Lachenal's body, which had fallen 28 meters deep. Back in Chamonix, his remains were guarded by his Annapurna companions, Maurice Herzog and Gaston Rébuffat.