What external events serve as a reminder to Ralston that he is lucky despite his risky adventures?

Ralston flirts with many close calls during his many expeditions. In one instance, he is one step away from falling with a fragile cornice that plummets when hiking on Mount Holy Cross. During that same time, he comes home to find two of his friends are in the hospital with injuries from separate skiing and snowboarding accidents. Although Ralston is resourceful, luck also plays a role.