Details at time of disappearance: Greub was last seen in the Cloud Peak Wilderness in the Bighorn Mountains in Johnson County, Wyoming on August 10, 1976. She was hiking with two female friends and decided to rest near the trailhead while the others climbed Cloud Peak without her. When they returned at 5:00 p.m., she was gone. She wasn't carrying any supplies when she disappeared, only candy.
Because Greub was having marital problems at the time of her disappearance, there was speculation that she left of her own accord. She lived in Casper, Wyoming at the time of her disappearance.
An extensive search, involving 200 to 300 people and covering about eighty square miles, turned up no indication of her whereabouts, and the search efforts were called off after two weeks. There has been no indication of Greub's whereabouts since 1976.