When Rob Hall (Jason Clarke)'s team is asked why they are climbing Mount Everest, everyone answers "because it's there," a motto of mountain-climbers worldwide. In a 1924 interview, George Mallory, an English mountaineer who took part in the first three British expeditions to Mount Everest, responded with the same answer when asked why he would risk his life to become the first person to summit Everest. Mallory disappeared during a summit attempt in June 1924. His body was found in May 1999, just under 700 meters from the top.
On 18 April 2014, while the second unit crew was shooting remaining scenes of the film at Camp II on Everest, an avalanche struck, killing 16 Sherpa guides - more than the 1996 disaster on which this picture is based. The Sherpas were carrying supplies to camps in advance of the start of the summer climbing season. There were no injuries or fatalities affecting the film crew; the production was not present where the disaster took place, but they were nearby. Filming had to be postponed.
Most of the radio calls are lifted verbatim from the real calls sent from the mountain on that fateful day.
Director Baltasar Kormákur demanded several takes for the scene featuring yaks crossing a bridge, which caused the animals to become irritated. When a helicopter came in for a wide shot, one of them suddenly started to stampede towards actress Naoko Mori, who plays a climber standing on a bridge 1,000 feet in the air. Josh Brolin and Jason Clarke, together, grabbed the animal by its horns before it sent her or another actor or crew member over the cliff.
To train for their roles, Jake Gyllenhaal and Josh Brolin went mountaineering in the Santa Monica Mountains.