Remote-control copters propel Colorado rockfall mitigation efforts

What can make many of Colorado's highways spectacular can also make them deadly.

CDOT senior geologist Alan Hotchkiss takes pictures along Highway 82 last week.
Troy Hooper

Particularly stretches of road that meander through canyons with walls that shoot high above, and where rocks of all sizes could at any moment come tumbling down. “Out of the Canyon,” the true story of an Aspen man who lost his family in a rockfall tragedy in Glenwood Canyon, is but one example. There have been nine fatalities as a result of rocks hitting cars on Colorado highways since 1999, including one that claimed the life of a motorist in Snowmass Canyon in August 2009.

But those are rare occasions. More often, rock slides damage and close Colorado's mountain roads.

Armed with $4.13 million to mitigate rockfall hazards this year, the Colorado Department of Transportation is putting several projects in the fast lane, including one in Shale Bluffs. The state is spending $1.5 million on that section of Highway 82 near Aspen to drape netting between mile markers 35 and 37. The Shale Bluffs project initially was scheduled to begin in 2013 but FASTER (Funding Advancement for Surface Transportation & Economic Recovery) money accelerated the work.

Crews are also evaluating Highway 133 over McClure Pass where they are considering rock scaling, blasting and netting. About $1.2 million is penciled in for the project, which could start in spring 2011.

In Glenwood Canyon, crews are repairing and improving existing rockfall fences along Interstate 70. The state has earmarked $600,000 for the project, which, like the one for Shale Bluffs, is already under way.

To get a better perspective on work that needs to be done, CDOT employs a small fleet of remote-control helicopters and airplanes rigged with cameras that are used to snap aerial photos.

A camera is attached to the bottom of this bird.
Troy Hooper

“We come out here and rate rockfall sites every five years. We're also doing aerial photography of each site. Instead of just a ground view we have a view from the air of what that entire site looks like and what some of the things may be causing the rockfall so at a later time we can come back and mitigate those things,” Hotchkiss explained. “These pictures are great to take because what it allows us to do is take a picture in time to see what it looked like a year, five years, 10 years, 20 years from now.”

The remote-control helicopters and airplanes cost about $3,500 and $5,000, respectively, and are built by Wilbur, who started Eye in the Skye Aerial about 18 years ago. CDOT is his only customer.

“It used to be fun, but now it's a job. It's very, very serious,” Wilbur said.

Dave Wilbur is at the controls.
Troy Hooper

There are 24 of them on Highway 82 and 20 of them on Highway 133, most or all of them rated high.

Hotchkiss and Wilbur are documenting all of them with the remote-control aerial photographs.

“It's a quick operation,” Hotchkiss said. “We're rarely in a location longer than 5 minutes, then off we go.”

Other sites where state officials are mitigating rockfall include I-70 at Georgetown Hill, where $1.4 million is earmarked, U.S. 285 in Turkey Creek Canyon near Bailey, where as much as $300,00 could be spent, and Highway 145 at Norwood Hill in the Telluride area, where $1.7 million is in the budget.