FALLING ROCK—California, Yosemite Valley. Michael Cannon (23) and Mark Richey (19) had just come off the Steck-Salathe route on Sentinel Peak. Richey had tied himself to the wall and Cannon was behind a large flake on a sizeable ledge. The next thing that Richey knew, the ledge gave way from under Cannon, resulting in a 600-foot fall.

Richey felt that the ledge was very adequate, and had appeared to have a number of other climbers do the same thing that Cannon had done. Richey was able to Class 3 the descent route to report the accident, arriving at the ranger station at 11 p.m. (Source: Charles Farabee, Yosemite National Park.)

Analysis: Cannon’s death occurred when a huge block he was standing on decided to break off. There was no way to predict when the block would break off and it would be unrealistic to say Cannon should have been clipped in because the block was large enough that most climbers could have felt secure enough to walk around on it unroped or not clipped in. (Source: Tim Setnicka, Yosemite National Park.)