Science Daily reports that researchers have conducted the first detailed analysis of deaths during expeditions to the summit of Mt. Everest. They found that
most deaths occur during descents
from the summit in the so-called "death zone" above 8,000 meters, and also identified factors that appear to be associated with a greater risk of death, particularly symptoms of high-altitude cerebral edema. The big surprise that the data indicate those deaths aren't primarily from avalanches or falling ice, as had long been believed.