Joseph Laurence Halpern was a 22-year-old doctoral candidate in the summer of 1933 when he disappeared from Rocky Mountain National Park. He had been on a road trip with his parents and friend Samuel Garrick and was camping with them in Glacier Basin. On August 14, Halpern and Garrick day-hiked the Flattop Mountain Trail; after reaching the summit Halpern chose to continue toward Taylor Peak while Garrick turned back. They agreed to meet at the Bear Lake Trailhead at 6:30 p.m., but Halpern never arrived.

A ranger-led search began that night and grew to more than 150 volunteers, but efforts were hindered by a snowstorm and turned up no trace. Park peak registers showed no record of his name. Over subsequent years there were unconfirmed sightings around the country and speculation he might have used the alias Louis Hollenbuck, but none were substantiated. Relatives provided DNA to authorities in case remains are ever identified. The disappearance remains unsolved.