Final answer:
Boukreev sees flares fired by the missing hikers during his second rescue attempt.
Step-by-step explanation:
During his second rescue attempt, Boukreev saw flares fired by the missing hikers that alerted him to their location. The flares provided a visual signal that helped Boukreev locate the missing hikers in the vast wilderness. This was a crucial clue for their successful rescue. In the context of a second rescue attempt, Anatoli Boukreev, a mountaineer involved in the 1996 Everest disaster, did not see flares, tracks in the snow, or receive a distress signal. Instead, during his second rescue attempt, Boukreev was guided by the faint glow of headlamps in the distance which alerted him to the location of the missing climbers, a fact chronicled in the book 'The Climb' by Anatoli Boukreev and G. Weston DeWalt. This incident emphasizes the perilous nature of mountain rescues and the reliance on limited visual cues in harsh conditions.