Abstract: At 10:15 a.m. on July 23, 2016, an employee was attempting to get a belay device un-struck from the face of the Owing-Spalding rappel on the Grand Teton Mountain. The employee was wearing a Mammut Climbing harness, using 9/16 8 foot synthetic flat strap runner as a positioning device. The employee was using two 20 meter climbing ropes to lower clients to the upper saddle floor in a belayed rappel. The employee was also wearing a climbing helmet. As the employee was working to un-stick the rappel device, the employee either unhooked his positioning device, or the positioning device broke, or the positioning device knot untied resulting in employee falling 120 vertical feet to the floor of the upper saddle. The employee then tumbled over the edge of Valhalla Canyon on the east face falling approximately another 2280 feet down the mountain side. The employee was killed and received very traumatic injury's to the entire body.