Pitkin County tweaks alignment of proposed Redstone to McClure Pass trail, adds underpass

New route features an underpass below the summit

Pitkin County has refined its proposal for a trail between Redstone and the summit of McClure Pass to get hikers and bikers farther away from Highway 133 near the summit.

Pitkin County Open Space and Trails wants to realign less than 1 mile of trail away from the final sweeping, left-hand turn at the top of the pass. Instead, it is proposing an underpass of the highway, then a more direct route to the summit south of Highway 133.

The proposed refinement was unveiled Tuesday in a joint meeting of the Pitkin County Open Space and Trails board of trustees and Pitkin County commissioners.

“To me it’s a game changer,” said Howie Mallory, a member of the open space board. “I’m very much in favor of the alternate route.”

The blue segments show realignments favored by Pitkin County on the proposed Redstone to McClure Pass Trail. The realignment on the left would avoid rockfall terrain on the north shoulder of Highway 133.
Courtesy image

The board of trustees voted 5-0 to support the alternate route Tuesday. The county commissioners also gave their blessing to refining the proposal.

The U.S. Forest Service is reviewing the proposal under its National Environmental Policy Act guidelines. The trail segment is about 7 miles. About 5 miles is on national forest. The 2 miles closest to Redstone would be constructed along the west shoulder of Highway 133.

The idea for an altered alignment near the top of the pass sprouted during a site visit that involved Pitkin County, the Forest Service, the Colorado Department of Transportation and various consultants. CDOT officials warned that the top mile of the pass is susceptible to rockfall and that a trail on the north side of Highway 133 would likely sustain extensive damage on any given year. Consultants said an underpass of the highway, about 1 mile from the summit, could likely be constructed for about $100,000, according to Gary Tennenbaum, director of the open space program.

Underpasses in the Roaring Fork Valley are expensive because they typically involve relocating utilities and dealing with a high water table. Neither of those challenges will be presented at the McClure Pass underpass, Tennenbaum said.

The expense of the underpass would be offset within a decade from lack of maintenance required if the trail was built on the north side of Highway 133 in the rockfall zone, he said.

The underpass also would prevent the need for trail users to cross Highway 133 at the summit to get to a large parking area at the start of the Raggeds Trail, a backcountry route.

“Really, truly this is a much better user experience,” Tennenbaum said at the joint meeting.

Pitkin County wants to build a trail in the upper Crystal River Valley, between Redstone and McClure Pass. This picture was taken in the upper valley in September 2017.
Scott Condon/The Aspen Times

CDOT also suggested a refinement to the plan at the bottom of McClure Pass. It suggested moving a proposed parking area about 600 feet south to an area with better sight lines along the highway and bigger capacity for vehicles. The county embraced that suggestion. It will require building a short spur from the parking lot to the main trail.

From the base of the pass to the summit, the proposed alignment follows an old roadbed as its snakes its way up several switchbacks. Tennenbaum said the switchbacks “aren’t super steep.”

Open space board member Michael Kinsley asked if the alignment would create a safety risk for hikers encountering bikers on a fast descent.

“I’m guessing these switchbacks are going to become a course for mountain bikers,” he said.

Tennenbaum said the switchbacks would prevent cyclists from picking up too much speed.

“It’s not going to have features on it like jumps and all that,” he said.

The Redstone to McClure Pass summit section is the latest portion contemplated in a Carbondale to Crested Butte Trail. Pitkin County previously built about 6 miles of trail alongside Highway 133 from Carbondale to the BRB Campground.

After two years of planning and public review, the Pitkin County Commissioners adopted the Carbondale to Crested Butte Trail Plan in December 2018. It’s an outline for an 83-mile route.

“All segments can stand alone, so if no other segments are completed, all created trails will connect people to places or trailheads,” said a memo prepared by the open space staff for Tuesday’s meeting.

The Redstone to McClure Pass summit section was picked to pursue first because of fewer perceived engineering and environmental challenges. However, it is facing significant opposition from residents of the Crystal River Valley, according to a sample of letters submitted to the Forest Service as part of its review.

There is no timetable on pursuit of approvals for trail segments between KOA Campground and Redstone.

(Editor’s note: This story was updated to clarify the underpass is for all non-motorized uses.)