I-70 reopens through Glenwood Canyon

Gov. Polis announces an “ahead of schedule” reopening for the interstate

Colorado Gov. Jared Polis looks at a map of drainages inside Glenwood Canyon created by the White River National Forest Service while touring the debris slide damage to Interstate 70 on Wednesday morning. Polis announced the reopening of I-70 on Saturday morning, Aug. 14.
Chelsea Self / Post Independent

Interstate 70 through Glenwood Canyon is now open, Gov. Jared Polis announced in a news release around 7:30 a.m. Saturday.

“Our team has worked tirelessly to get Glenwood Canyon on I-70 opened as soon as possible, and we have made each minute count. I’m thrilled that we are delivering a few hours ahead of schedule. Every moment counts. I want to thank Shoshana Lew for her leadership on this effort as CDOT has worked day and night to safely clear a path. It has been an all-hands-on-deck effort to get the canyon reopened from the mudslides which covered parts of the highway with 15 feet of rock and sludge,” Polis said.

The stretch of I-70 between Dotsero and Glenwood Springs initially closed July 29 after unprecedented monsoonal rains showered between 2 to 4 inches in about an hour throughout Glenwood Canyon.

This caused substantial debris flows stemming from the Grizzly Creek burn scar to envelope sections of both eastbound and westbound lanes on I-70.

Not only did the July 29 rain cause major infrastructural damage, a surge of heavy mud, rock and loose earth initially trapped more than 100 motorists either in the Hanging Lake Tunnels area or in the nearby Bair Ranch exit. Everyone was eventually evacuated by CDOT crews with the assistance of Colorado Highway Patrol.

“A similar rainfall event occurred overnight between Saturday, July 31 and Sunday Aug. 1, 2021. I-70 has been closed since the first of these two major storm events on July 29,” CDOT Chief Engineer Stephen Harelson wrote in Aug. 8 letters sent to the U.S. Federal Highway Administration, which included assessment surveys and requests for funding. “The slides that closed the road earlier in July inundated the facility with mud but did only moderate damage to the infrastructure. The storms of July 29, 2021 and Aug. 1, 2021 caused considerable damage to at least four discrete structures in the Canyon and possibly more that will only be known when the debris is removed from the affected areas.”

The monumental disaster is considered by National Weather Service officials to be a 500-year event.

“At the Blue Gulch drainage, Westbound I-70 experienced the loss of the uphill barrier, culvert inlet drop structure, post tensioned slab overhang, parapet and structure rail,” Harelson wrote. “In some areas, the post tensioned slab is intact but the parapet has been removed and the post tensioned strands are compromised.”

Initial estimates put the cost of repairs at $116 million — which Gov. Jared Polis requested on Aug. 6 from the federal government. That amount, Harelson writes, could change in the weeks to come.

“We are performing damage assessments throughout the area,” Harelson writes. “At this time it is not possible to provide exact cost estimates, however, damage to Federal-aid highways is currently estimated at $116 million. CDOT expects to be able to provide a more accurate estimate in 8-10 weeks.”

The catastrophe marked one of many debris flows to have occurred in Glenwood Canyon throughout the summer.

Harelson stated that “at least 19 separate debris flow events” have been recorded in Glenwood Canyon between June 26 and Aug. 3. Meanwhile, flash flood warnings alone caused CDOT officials to close I-70 in Glenwood Canyon 12 times between June 26 and July 28.

In addition to mitigation and repair efforts on I-70, CDOT said alternate routes such as Cottonwood Pass will also likely require $50 million for improvements to withstand heavier traffic while also providing resiliency.

“In addition to the immediate roadway damage, the debris flows have severely impacted the Colorado River. There are approximately five locations where debris flows have severely obstructed the river flow at this time,” Harelson stated. “At several locations, the debris deposited in the river has created river-wide obstructions raising the river water level over the multi-use recreational path and threatening the eastbound I-70 retaining walls and multi-use recreational path with increased scour and damage.”


● CDOT administration (non-maintenance staff) costs = $1 million

● Debris removal costs (includes maintenance staff costs) = $4 million

● Supplemental traffic control services (contractor) costs = $1 million

● Visible damage estimates caused by event damage or debris removal hauling costs = $20 million

● Assumed damage repair estimates (non-visible) costs = $20 million

● Potential geohazard mitigation at several locations = $5 million

● Construction Management and Construction Engineering costs = $5 million

● Impacts to existing State Highway alternate routes (as a result of I-70 closure) costs = $10 million

● Future Resiliency and Redundancy Study costs = $50 million


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