But when Richardson didn't return to work the following Monday, search teams from the Blaine County and Custer County sheriff's offices, as well as Idaho Mountain Search and Rescue
, began scouring 51-square-miles of the Pioneer Mountains, according to the Idaho Mountain Express.
The search involved 2,000 man-hours and up to 50 trained search-and-rescue volunteers in the field at a time.
Despite using civilian, Lakota and Black Hawk helicopters, drones, search dogs and five mountaineering teams, no trace of Richardson has been found.
reported cold weather, 30 mile per hour winds, fog, snow and ice have challenged search crews. Temperatures along the ridge dropped to 15 degrees. The teams searched high elevation areas, reaching up to nearly 12,000 feet and used gris systems to cover all possible areas of Richardson's trek.
"We've conducted a thorough search of the area and at this point feel further searches would not yield any new clues," Blaine Country Sheriff Gene Ramsey told the Mountain Express.
"Based on the widespread area that has been searched and the nature of the terrain, we feel that we cannot further endanger the safety of our technical teams."
Flyers with Richardson's picture have been handed out to more than 50 hunting camps in the search area in hopes he will turn up.
Richardson's car was parked at the Summit Creek trailhead. His tent, sleeping bag and coat were later found in his home. He's always been drawn to the outdoors, according to his parents. It's not unusual for him to wander more than 20 miles in a day, according to a report by KTVB
. He especially enjoyed bouldering—a form of rock climbing that doesn't rely on ropes or safety equipment.
"The mountains are always where he found his true strength," said Richardson's mother, Stephanie. A fundraiser set up through the CrowdRise website raised more than $15,000 as of Sept. 23. The money will be used to fund further search efforts by family, volunteers and hired help.
Search and rescue teams say they have exhausted the terrain looking for 25-year-old Lucas Richardson, a Hailey resident that went missing after he journeyed up Summit Creek Trail on Saturday, Sept. 12.