The Colorado Dept. of Transportation says it doesn’t know when Interstate 70 through Glenwood Canyon will reopen after Sunday’s rockslide. CDOT crews spent most of Monday blasting to break up the larger boulders, while CDOT geologists assessed the rock cliff above the highway and determined that it is too unstable to remain in place without rock scaling. Crews met Tuesday to determine how to control the existing rock.

CDOT has implemented emergency contracting procedures while it continues to develop repair plans and seek bids, which it expects to receive in the next day or two, according to Mindy Crane, CDOT public relations manager. CDOT hopes to have a contractor in place by the end of the week.

The slide occurred at midnight, just west of the Hanging Lake Tunnel in Glenwood Canyon, punching holes in a bridge and dumping boulders the size of semi-trucks on the highway, closing a 17-mile stretch of the road Monday morning. Approximately 20 boulders fell onto the interstate ranging in size from 3 ft to 10 ft in diameter. The largest is estimated to weigh about 66 tons. No one was injured in the slide.

CDOT geologists have attributed the slide to a freeze-thaw effect caused by warm spring weather, Crane said.

The rocks smashed holes in the elevated sections of the roadway—the largest of them in the westbound lanes, measuring 20 ft by 10 ft. Another hole in the lower eastbound lanes measures 6 ft by 6 ft.

“There are a half-dozen other holes and dips in the roadway, as well as areas where rocks are embedded,” said CDOT spokesperson Stacey Stegman. “Rocks are scattered over 100 yd of roadway.”

Also damaged are three sections—about 120 lin ft of steel guardrail and 100 lin ft of median barrier. The slide is being compared by CDOT to a similar one that occurred on Thanksgiving Day 2004, which required $1.2 million in repairs. The department’s current rockslide mitigation budget for 2010 is $2.4 million.

Gov. Bill Ritter issued a disaster declaration on Monday afternoon, allowing the state to seek funding from the Federal Highway Administration to help pay for repairs, which could take weeks, Stegman said.