The well-known climber Ed Viesturs plays himself in the movie. He also worked as a trainer for the actors.
The script was originally meant to be a sequel to Cliffhanger (1993).
While the actual 28,000-foot K2 is in the Karakoram Range in Pakistan, Mt. Cook in New Zealand served as the backdrop for all scenes involving the famous peak.
The toeless feet of character "Montgomery Wick" seen at the beginning of the film actually belong to mountaineer Mark Whetu, who lost his toes while spending a night outdoors above 28,000 feet during a 1994 attempt on Everest.
Montgomery Wick's name is an obvious reference to Thomas Montgomerie and Jim Wickwire. Montgomerie discovered K2, and Jim Wickwire was the first American to climb K2. Wickwire also lost several toes on the mountain, similar to the character Montgomery Wick.