For more than ten years, Hoey worked as a professional guide on Mount Rainier and on Mount McKinley, and she also climbed on more distant ranges.[2] Hoey climbed Pik Lenin in 1974 and was a part of the 1976 Nanda Devi expedition.[2]
Hoey also worked for Dick Bass, as safety patrol chief at the Snowbird ski resort.[3] She befriended him and accompanied him on his own successful ascent of Mount McKinley, and he was a member of her climbing group when she perished on Mount Everest, in 1982. When Bass eventually summitted Everest in 1985, he dedicated his ascent to her.[4]
Expedition teammate Jim Wickwire said that he and Hoey were perched on a 45-degree rock slope at about 26,600 feet (8,100 m), carrying gear to establish Camp 6, with the expectation of heading for the summit in the next day or two.[3] Wickwire said that Hoey leaned back to let him go ahead, and a buckle on her harness opened, releasing her from the fixed rope and sending her plunging down 6,000 feet (1,800 m) into a crevasse.[5][3]
Hoey's body was never recovered. Whittaker said, "I can't think of a more beautiful resting place; she fell into the prettiest place that ever was."[3] Whittaker cited Hoey's death as a contributing factor to the expedition's failure to summit Everest, saying: "If Marty had been with us, we would have made it."[3] The 16 remaining team members, all men, would make a third and final attempt, and ultimately be turned back, shy of the summit, by fierce weather.[3]
Hoey was one of ten fatalities on Everest in the 1982 climbing season, but the only American.[6] Some other fatalities that season were noted British climbers Peter Boardman and Joe Tasker.[6]
