According to source:
On Friday, June 17, 2016, Floyd Roberts III (52), set out for a hike together with friend Ned Bryant and Ned’s daughter Madeleine Bryant, for a trip to the Western part of the Grand Canyon in Arizona.
That fateful backpacking adventure was the last time that Floyd would be seen alive. He vanished into thin air after deciding to climb a hill using a different route to the Bryants in the Grand Canyon-Parashant National Monument.
The two friends met when they were about 10 years old in Princeton, N.J., and Roberts was the best man at the wedding of Ned and Heidi Bryant.
Floyd went on to live in Huntsville, Alabama, where he worked for NASA and from there he went on to teach computer programming and game design at Middleton High School in Treasure Island, Florida.
The friends first started hiking in the area in 1992 and sometimes Bryant would go on his own but for two decades, Roberts had been his regular hiking buddy. The Bryants were board members of the Grand Canyon Hikers and Backpackers Association. Although Roberts hadn't been hiking for a few years, he was an experienced hiker. and the group had visited the area back in 2011 without incident.
The group planned a 9 day hike on the Shivwits Plateau that would exit the canyon via Separation Canyon and were intending to spend the first couple of days camped alongside the river. They anticipated they would finish their hike on June 26.
Floyd was 170 lbs, 5'11" tall, brown/grey hair, brown eyes and was last seen wearing a red long-sleeved shirt, blue denim jeans, multi-colored mesh Nike Free sneakers, large blue Lowe Alpine Contour backpack, and white-rimmed sunglasses with orange lenses. He brought two gallons of water with him, and enough food to last a week.
Before they reached the trailhead, the group reached a hill at around 4.45 pm. They decided to take different routes. Ned Bryant and his daughter went up and over, Floyd contoured around the hill. At that point, the group separated and agreed to meet at the other side of the hill.
When Ned Bryant and his daughter reached the other side of the hill, they waited for Roberts. They got anxious and started looking for him. They retraced their steps; they went back to the road. But nothing. Floyd had mysteriously vanished at that point.
Floyd was last seen near Kelly Tanks heading towards Trail Canyon/214 Mile Canyon (Shanley Spring area) towards the river but may have descended into 209 Mile Canyon. The area is in the extreme western portion of Grand Canyon, in an area called the Grand Canyon-Parashant National Monument.
Grand Canyon-Parashant National Monument is a very remote and undeveloped place jointly managed by the National Park Service (NPS) and the Bureau of Land Management (BLM). The name Parashant is derived from the Paiute word Pawteh 'ee oasoasant, meaning "tanned elk hide," or "softening of the elk hide." There are no paved roads into the monument and no visitor services. The area is 1,048,325-acres (424,242 ha). Elevation ranges from 1,230 feet (370 m) above sea level near Grand Wash Bay at Lake Mead, to 8,029 feet (2,447 m) at Mount Trumbull.
Ned Bryant and his daughter decided to camp for the night and then walk to an area with cellular reception and was first able to report Roberts missing to the National Park Service on Saturday, June 18 at around 3 pm.
Temperatures in the Grand Canyon National Park were around about 92 degrees (33.3°C) on the afternoon when Floyd was reported missing and rising to 110 degrees on a subsequent couple of days. So it was hot, but Floyd had a reasonable supply of water.
Initially, around 15 people were involved in the search, including sniffer dogs. Eventually, seven ground teams and the National Park Service (NPS) helicopter were involved in a search area covering over 10 square miles and in an extremely remote, rugged area of the canyon. Searchers from Grand Canyon-Parashant National Monument and Mohave County helped the Grand Canyon National Park Search and Rescue team. The NPS also worked with the Coconino County Search and Rescue. The area was rugged and covered in thick brush and transportation to the area took several hours. A base camp had been set up near Kelly Tanks with shade shelters, water, and other resources for the search teams.
After 6 days in the heat and tough terrain, the search was scaled back on June 24 and the authorities went into limited but continuous search mode.
At that point, there were few clues about where Roberts might be. While there were footprints to follow at one point, rescuers could not confirm they belonged to him.
Since that day in 2016, no trace of Floyd has been found. Disappeared off the face of the earth, despite being an experienced, well prepared, hiker. Perhaps, just a case of hyperthermia in the 100 degrees plus heat and a stumble in the wilderness.