COLLBRAN, Colo. - Unable to put search teams on the ground in the area of a massive mudslide near Collbran, the Mesa County sheriff says they are now presuming that three missing men are dead.
"We are essentially in a recovery effort at this point with our three missing people," Sheriff Stan Hilkey said, adding that the families are aware.
Fifty-one-year-old county road worker Clancy Nichols, his 24-year-old son Danny and 46-year-old Wes Hawkins have been missing since Sunday after a rain-saturated ridge collapsed.
Hilkey said the families of Clancy, Danny and Wes understand the dangers of putting searchers on the mud flow.
"What remains is visual monitoring and over-flights with both unmanned and manned flights," Hilkey said. "This remains an unstable area."
Hilkey believes the three men were checking on why their water flow from Salt Creek had stopped when the slide occurred Sunday night.
"These three people we are missing are all ranchers. They were in the area doing what ranchers do," Hilkey said. "Water is lifeblood. They were investigating why this water had suddenly stopped flowing the way it was supposed to be flowing."
Officials believe that while the men were investigating the water flow problem, they likely found a small slide. Hilkey believes while the men were checking out the first slide, the larger slide hit.
Hilkey showed a Google Maps image of the slide and said, based on discussions with the men's families, that he believes the men were on a road, somewhere in the middle of the slide area when the hillside gave way. Hilkey believes the debris flow carried the men into the bottom third of the slide.
The worst case scenario, Hilkey said, is that the men will not be found.
"The family has acknowledged that, we have acknowledged it, but it doesn't deter our interest in doing everything we can," Hilkey said.
-- Ground search --
Hilkey explained that the search on the ground was suspended Tuesday because of fears that a buildup of water on the hill could cause another "major" mudslide.
"It's still determined to be unsafe," Hilkey said. "[What] we’d 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 sheriff said teams may not be able to get on the slide until the summer.
"We are in peak runoff season and we will continue to be for quite sometime," Hilkey said. "We believe that it may be well into the summer, into a drier period of time, before it is ever deemed to be safe to be on this (mudslide) to do more searching."
The work done Tuesday was entirely from above, involving high-resolution aerial photography.
The mudslide is estimated to be 2-to-3 miles long, at least three-quarters of a mile wide at the top, and about 250-feet deep, in many places. The surface area of the slide is estimated to be about 706 acres.
-- Depression forming behind the slide --
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 the water is filling behind that area and the rest of the slide is dry.
"(The slide) has cut off the flow of West Salt Creek," White said. "There is a significant amount of runoff flowing into the depression."
White is concerned this depression will put pressure on the slope around it and the slope will eventually fail.
"We don't know when that could occur," White said. "It likely won't remain a reservoir."
However, White said it is possible the depression could fill up for years and years, eventually flowing over the top.
"This material is more stable than we think and we're just going to have a long-term pond up there, which is a scary thought because we know eventually that will fail," White said. "That is the big concern now is that we will see a second pulse of debris that will come down this existing landslide."
White said that second flow of mud and debris could follow down the existing path or change directions.
When asked about making this massive pool of water a permanent reservoir, White said no.
"It's just a chaotic, disturbed mass that is more like a soil than rock, " White said. "It is highly unlikely that could remain as a permanent reservoir."
White said the worst case scenario is that it fills up with water and sits for years and people forget about it.
"We might have another significant rainfall and if it were to breach, we would have flooding extending all the way down Salt Creek," White said.
Hilkey said officials are trying to create a monitoring plan.
"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.
White said this area has seen landslides before.
"The Grand Mesa is ringed by landslides," White said. "What's unusual is just the size."
-- Even Powderhorn Ski Area is a landslide --
White said the whole terrain up there [on Grand Mesa] is landslides.
"The ski area up there is on a landslide," White said. "There's a lot of landslide that ring Grand Mesa. CDOT has problems with its roads going up Grand Mesa on both sides. "
"There's enough slope and enough water where it behaves more like a fluid -- you get those long toes that can travel down those drainages," White said.
-- Cause of slide --
The Grand Mesa area had seen several days of heavy rain.
"We believe the runoff of water from the Grand Mesa is what triggered the slide," Hilkey said. "No doubt it’s tied to the rain."
White was asked if the slide could be attributed to oil and gas drilling in the area.
"I don't think oil and gas drilling had anything to do with the slide," White replied. "I don’t see how it could have."
-- Natural gas production facility shut down --
During Tuesday's news conference, Hilkey put up a photo that showed the mudslide came within feet of several energy industry tanks.
The West Slope Colorado Oil & Gas Association said one active natural gas production facility was affected by the mudslide.
"The threatened well pad hosts three active natural gas wells located along Salt Creek Road east of the Town of Collbran," officials said.
While officials said there were no signs of spills or releases, the natural gas wells were shut down manually and connective pipelines were depressurized and drained.
-- Advice from Washington state officials --
Hilkey said he talked to search and rescue officials in Washington state where 43 people died in a mudslide in March. Hilkey said that Washington state officials gave him very valuable information about where to search and what can be done.
"They gave us great advice about where to start searching first," Hilkey said. "They were extremely helpful."
Whereas the Washington mudslide was measured in feet, the Collbran mudslide is being measured in miles, he said.
"While their slide was small, their loss was enormous and tragic," Hilkey said.
-- Statement from Town of Collbran --
"The Town of Collbran is working closely with Mesa County on the massive landslide that occurred east of the town in the Salt Creek drainage. Collbran will make whatever resources are needed avialable to the emergency crews. We will continue to closely monitor the situation and work with Mesa County to keep town and area resident informed. Our hearts and thoughts go out to the families and community leaders that have suffered losses from this event. We will provide timely public information statements that are coordinated with Mesa County to keep the community informed about the situation."