Three men — a county road worker, his son and another man — remained missing Tuesday after an all-day search of the lower portion of the Colorado landslide, which measured a half-mile at the top and trailed some 3 miles downhill.
Authorities late Monday identified the men lost in the massive slide that hit a remote part of western Colorado.
Fifty-one-year-old Clancy Nichols, his son Danny Nichols, 24, and Wes Hawkins, 46, have been missing since Sunday after a rain-soaked ridge collapsed near Collbran.
All three of the men live on local ranches, authorities said. They had been in the area investigating the effects of a previous, smaller mudslide.
Hawkins works for a local water conservation district, Clancy Nichols works for the Mesa County Road and Bridge Department, his son Danny is a geologist, according to the Denver Post. They had been looking at some cracks in the mountainside spotted by Hawkins' father, Melvin "Slug" Hawkins, the Post reported.
They were traveling in a pick-up truck and a 4-wheeler when the second mudslide occurred, officials said.
"I know (the missing are) residents of what we call the Collbran-Mesa area," Heather Benjamin with the Mesa County Sheriff's Office told NBC Denver affiliate KUSA.
"Those are two small towns up there on the Grand Mesa, which to us would typically indicate that they're familiar with the terrain. They're probably very outdoorsy, probably very prepared for the severe weather and being stuck in the mountains overnight, and those kinds of things."
Searchers looked for the men Monday only at the lower end of the slide because upper section is considered too unstable.
The search is scheduled to resume Tuesday.
"Everybody on this mountain is praying for a miracle right now — hoping they're stranded and avoided," said Mesa County Sheriff Stan Hilkey said of the community of Collbran, which he described as "tight-knit."