This footage of the mudslide area was taken by the Mesa County Sheriff's office on Monday, May 26, 2014. Karen Berry, the interim State Geologist and Director of the Colorado Geological Survey, narrated the video and shared what she saw with CPR's Mike Lamp.

Laser and radar technology is being used to remap the area of a massive mudslide in western Colorado, where three men are still missing.

Mesa County officials say two days of flights over a large area from Collbran to Vega Reservoir are underway. About 87 flights over the area will remap the topography of the slide and are aimed at getting a better sense of the new landscape.

The half-mile-wide by 3-mile-long slide, which was triggered May 25, is about 11 miles south of Collbran.

A memorial service in Collbran was held on Sunday for the three missing men — 51-year-old Clarence "Clancy" Allen Nichols, his 24-year-old son, Daniel Allen Nichols, and 46-year-old Wesley "Wes" Melvin Hawkins.

The Grand Junction Daily Sentinel says people from the Collbran area packed the Plateau Valley School gymnasium Sunday.

Authorities say they were swept away in a mudslide a half-mile wide and 3 miles long May 25, about 11 miles south of Collbran.

They had been checking on irrigation problems caused by an initial slide when a large chunk of a ridge broke off, sending soggy earth spilling like wet cement. Their bodies have not been found.