Rock slides are fairly common in the canyon during spring thawing. The canyon is lined with granite and that tiny separations in the rock face can be moved apart by melting ice and snow. Another slide in the same location happened about 2 a.m. on Monday and triggered lane closures. Repairs must be done and debris removed before travel can resume. Explosives must be used to blast some of the boulders that landed on the interstate. The stretch of I-70 that has been closed is the state’s main artery from the Front Range to the Western Slope, including the popular resort destination of Aspen.CDOT officials advise motorists to take U.S. 40 as an alternate route. The detour could take up to 4 hours and adds 146 miles to a normal trip from Wolcott to Rifle. Eastbound motorists are encouraged to take the same route starting at Rifle and getting back on the interstate at Wolcott.