Workers will hike up the side of a Colorado canyon again Wednesday to figure out how they're going to handle a large, unstable boulder, which is threatening to fall on Interstate 70 after a rock slide forced the highway to close indefinitely.

The Colorado Department of Transportation says the threatening rock is about 20 feet in diameter and sits about 900 feet above the roadway. Workers were able to reach the rock on Tuesday, but not with enough light left in the day to deal with it. Those crews were also removing other rocks and debris from the canyon to prevent more rockslides.

CDOT spokesperson Mindy Crane says crews will hike up the canyon again on Wednesday to try to drill or blast the boulder to break it up, removing the danger to potential drivers on the highway down below.

Once the unstable boulder above the highway is removed safely, crews will begin to repair the westbound lanes which suffered massive damage from the initial rockslide.

About 20 boulders tumbled onto I-70 in Glenwood Canyon at about midnight Sunday. No injuries or damage to vehicles were reported, but the slide left holes as large as 10 by 20 feet in a bridge-like elevated section of roadway.

A 17-mile stretch of I-70 is closed in Glenwood Canyon from Glenwood Springs to Dotsero.

CDOT says it’s still hard to estimate when the East-West highway will be re-opened to drivers.

Governor Ritter has declared the area a disaster. That declaration allows the state to seek federal funding from the Federal Highway Administration to help pay for repairs.

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