On 25 December 1997, during a winter ascent of Annapurna, Dimitri Sobolev, Anatoli Boukreev and Simone Moro were swept away by an avalanche. Moro miraculously managed to save himself with an epic return to base camp, vividly recounted in the book "Comet on Annapurna". The bodies of Sobolev and Boukreev were never found. A commemorative chorten has been erected at Annapurna Base Camp in memory of the great Kazakh mountaineer.