'One little thing goes wrong and everybody on the scene is going to die' - Grand Canyon helicopter rescue teams under pressure as hikers succumb to extreme heat

Pilots in a Helicopter over the Grand Canyon.

Hikers exploring the Grand Canyon are being warned to come prepared for extreme heat after a surge in search and rescue helicopter call outs.

Emergency teams were mobilized for life-saving missions some 13 times in one week in May, according to a report in Outside.