Barnes was last seen hiking near the 6000 block of the right fork of Sardine Creek Road, in the area around the "House of Mystery" in Gold Hill, Oregon on September 1, 2002. She was carrying a green fanny pack at the time. Barnes had gone hiking that day with her sister. They separated to look for aluminum cans. They were supposed to rendevous at Barnes's sister's car, but Barnes never did and has never been seen again. She had been reported missing before when she was lost while hiking, but was found safe and was angry at her family for sending out a search party. As a result, this time her family waited 30 hours before informing the authorities.

Barnes may have been spotted on the day of her disappearance by a man who said she told him she was going back to her sister's car. Another witness might have seen Barnes at the valley of Rogue State Park. Tracker dogs traced her scent to the off-ramp of north Interstate 5. Police believe she walked down Sardine Creek Road to the highway. Two residents of the neighborhood report having seen her. None of these sightings have been confirmed. A week after Barnes disappeared, a man in Gold Hill found the bronze ski pole she used as a walking stick. He has passed a polygraph and is not considered a suspect in her case.

Barnes resided in the 100 block of Brookside Boulevard in Merlin, Oregon at the time of her disappearance. She is an experienced hiker and an ex-Marine who served in Vietnam. Her family does not believe she left of her own accord and think she may have been abducted, but little evidence is available as to her fate.