Hilkey said another slide is still possible.
"We're not able to do what we would like to do," the sheriff said. "What we would like to do is have every inch of this covered with people if we could. But we don't want to create any more of a tragedy than we already have."
The three men a county road worker, his son and another man were all from the close-knit town of Collbran. They volunteered to investigate when a rancher noticed his irrigation ditch stopped running.
The smaller mudslide was found to be to blame for the water cutoff.
When the men went to check on the damage, a huge chunk of the ridge sheared off, likely overwhelming them.
Hilkey has said the slide was most likely triggered by runoff from Grand Mesa following two days of strong rain.
No structures or roads were affected in the remote area, about an hour east of Grand Junction. A drone was used to try to detect heat sources from the missing near the edge of Grand Mesa, one of the world's highest flat topped mountains.
The Mesa County Sheriff's Office identified the missing as Clancy Nichols, 51, a county road and bridge employee; Danny Nichols, 24, Clancy Nichols' son; and Wes Hawkins, 46.
Clancy Nichols' brother, Bill, says he's holding out hope they survived the slide.
"We're praying for their safety," he told KUSA-TV. "We're praying for the safe return of the family members of Wes' family and for Clancy and Danny to come back."