Massive rockslide closes I-70 in Glenwood Canyon

By Kevin Flynn
Inside-Lane.com

A huge rockslide early Monday morning in Glenwood Canyon closed Interstate 70 in both directions between Glenwood Springs and Dotsero, forcing a lengthy detour of up to 150 miles for cross-state traffic.

The Colorado Department of Transportation said the slide punctured about a half dozen holes and divots in the two bridges on the west side of the Hanging Lake Tunnels. They carry I-70 over the Colorado River and Union Pacific Railroad, just west of the Shoshone Dam and the ramps that lead in and out of the Hanging Lake trail parking area.

I-70 in Glenwood Canyon has average daily traffic of 19,800 vehicles a day, according to CDOT traffic counts. This slide could result in more complicated traffic issues than a similar slide at the same location on Thanksgiving Day 2004. In that case, all of the significant damage was in the westbound lanes, and CDOT was able to restore two-way traffic in about 31 hours by shifting vehicles to one lane in each direction using the eastbound structure. Full repairs took two months.

But in this incident, both westbound and eastbound structures suffered significant damage. CDOT has to assess the situation more fully before deciding on a course of action.

Some of the boulders were the size of semi-tractors and will have to be broken up with explosives before they can me moved out of the road. One hole in the westbound lanes was estimated to be 10 by 20 feet, said CDOT spokeswoman Mindy Crane. In the eastbound lanes, there was a five-by-five-foot hole. CDOT’s chief spokeswoman Stacey Stegman went to the scene and reported the data back to Crane. There is limited mobile phone service deep in the canyon.

The slide occurred close to the same chute where a rockslide on Thanksgiving Day 2004 closed the road for a full day and forced a detour of one lane in each direction for two months while repairs were done. That slide punched several holes in the bridge deck including one that was 30 by 15 feet.

Those repairs were done by Kiewit Construction under a $681,775 contract that included a bonus for finishing early. CDOT spent a total of $1.2 million on the incident, including clean-up and rock-scaling in the chute to clear out other loose rock.

The new slide occurred around midnight and no one was injured. CDOT has an operations center inside the tunnel that is staffed around the clock to manage traffic.

Detours are daunting to long-distance traffic.

Drivers headed west can exit I-70 at U.S. 40 at Empire, head over Berthoud and Rabbit Ears passes to Steamboat Springs, then back to I-70 at Rifle via Craig and Meeker – a distance of 290 miles, or 150 miles farther than the distance from Empire to Rifle on I-70.

Other detours over CO 9 at Silverthorne or CO 131 at Wolcott add 115 miles and 142 miles, respectively, to the trip.

CDOT crews are assessing the damage before deciding how to proceed.

“We have no estimate as to how long the highway will remain closed at this time,” CDOT spokeswoman Stacey Stegman said. Crews were searching for the source of the rockslide first to determine whether it was safe to be in the area without more rocks coming down.

I-70 through Glenwood Canyon is an internationally acclaimed stretch of roadway that won award for its context-sensitive design and construction. Because of the high unstable cliffs, there are areas prone to rockslides. Read this comprehensive photo-filled feature about the history of I-70 in Glenwood Canyon at Matt Salek’s Highways of Colorado site.