COLLBRAN, Colo. - Collbran residents jammed a town hall meeting Thursday evening to learn more about the possibility of another mudslide.
Mesa County Sheriff Stan Hilkey has already warned residents of about 35 homes along Salt Creek Road to be ready to leave quickly in case there is another slide. The first slide was 2-to-3 miles long, at least three-quarters of a mile wide at the top, and about 250-feet deep, in many places. It also registered a 2.8 on the Richter scale.
Some are already packing up and leaving while others are keeping an anxious watch on the mountainside that slid earlier this week, presumably killing three of their neighbors -- Clancy Nichols, 51, his son Danny, 24, and Wes Hawkins, 46.
Officials believe that while the men were investigating a water flow problem, they likely found a small slide. Sheriff Stan Hilkey believes while the men were checking out the first slide, the larger slide hit.
During the meeting, Sheriff Hilkey apologized to the crowd for not being able to find the three men. Earlier this week the area was declared too unstable for any crews on the ground.
Now, authorities are working to avoid another disaster.
"What we're doing is trying to outguess the mountain," one official told residents at the meeting.
Experts said there is a "depression" or "pond" forming behind the slide. The depression is 1,600-feet long, 300-to-400-feet wide and possibly over 100-feet deep, according to geologist Jonathan White.
A preliminary study showed it could hold 700-to-800-acre feet of water, if it were to fill.
"Our biggest concern, is that entire slide did not all go at the same time," White explained. "There’s still a very large block of material up there."
White said that second flow of mud and debris could follow down the existing path or change directions.
Officials are working to create a monitoring system with cameras and GPS sensors to detect if pressure from the pooling water causes any movement in the slide.
"To monitor the movement of the existing slide, monitor the water that’s building up behind it at the very top and develop a threat assessment if we had another major slide event, which we believe is entirely possible," Hilkey said.
Incident commanders in Mesa County said they are looking to place remote cameras, GPS equipment and seismometers in the area to gather better information. For now, however, experts are primarily monitoring the area visually with manned or unmanned flights and two USGS satellites.
"The instability and current water saturation levels, along with the water pooling in the area behind the slide near its origin, are indicators that a further or additional slide and earth movement could happen any time," the county wrote in a May 29 blog post about the incident.
The goal, Mesa County said, is to build a warning system focused on these three tiers:
- Salt Creek Road residents from Highway 330 to the toe of the mudslide
- From Salt Creek Road to the town of Collbran
- Below the town of Collbran