Joseph Lawrence Halpern disappeared on August 14, 1933 after heading out on a road trip with his parents, and a friend from college, Samuel Garrick. During their road trip, they stopped at Black Hills in South Dakota and Yellowstone National Park, before stopping over at Rocky Mountain National Park.

On the day of August 14, both Joseph and Samuel ventured out on a hike on the Flattop Mountain Trail. The two started at Bear Lake parking lot, and hiked about 4.2 miles to the crest of Flattop Mountain. Once they arrived at the highest point of the mountain, Joseph expressed that he wanted to continue on with the hike, however, Samuel had grown tired and wanted to turn back. They both agreed to part ways, and Joseph continued ahead while Samuel headed back to the parking lot.

Samuel waited for Joseph at the parking lot, expecting him to turn around as evening drew nearer. But, when evening arrived, Joseph hadn't returned to the parking lot, and that was when he was reported missing.

The search for Joseph began the following day, and the search party included park rangers, along with over 150 volunteers and a party from the Civil Conservation Corps. Throughout the trail were route registers in which Joseph's name was not found in any of them. Not long after Joseph and Samuel parted ways, two hikers had spotted Joseph hiking west of Hallett Peak - this was the last location he was seen in.

Speculations as to where Joseph might have headed were either Chief's Head Peak, or Andrews Glacier. Both were described hazardous to hike in, particularly during the night.

Joseph Lawrence Halpern remains missing.