Final answer:
The Chinook helicopter faced challenges such as extreme cold, low oxygen levels, and hazardous terrain while attempting to reach climbers, making the rescue operation in a mountainous environment difficult.
Step-by-step explanation:
It was challenging for the Chinook helicopter from Joint Base Lewis-McChord to reach the climbers due to a combination of factors typically present in high-altitude mountain rescues. Such factors include extreme cold, low oxygen levels, and low barometric pressure, all of which are characteristics of an environment hostile to human life, as mentioned for climbers on Mount Everest. In addition, the local topography and potentially hazardous weather conditions can make it difficult to navigate and land helicopters safely in mountainous terrain.