Repair crews, under the glare of portable spotlights, toiled through the night in snowy conditions, but it could take months before the stretch of Interstate 70 is completely fixed, said Colorado Department of Transportation spokeswoman Stacey Stegman.
More than three dozen boulders landed on I-70 early Thursday, some embedded 6 feet deep. State officials closed 24-mile section of the main east-west artery through Colorado, and rerouted Thanksgiving Day traffic along an almost 220-mile detour to the north.
Transportation officials estimated that there was $1 million in damage.
No one was hurt in the rock slide because a truck crash had closed the road at the time. A rock slide in 1995 claimed three lives in the canyon that parallels the Colorado River.
Traffic was moving slowly but smoothly late Friday afternoon, said Paul Peterson at the 24-hour Colorado Department of Transportation control center.
"People have been extremely good, patient," Peterson said.
Geologists and engineers worked alongside the crews, trying to figure out what caused the slide. "This is the worst I've seen in my eight years," Stegman said.
The slide left holes in the decks of two bridges, damaged guardrails and knocked out two wall panels along westbound lanes of the mountain highway.
Diann Allen of Redondo Beach, Calif., was just 30 miles from her destination when she learned she wouldn't be traveling any farther on I-70 Thursday. She had been headed to Marble to meet her boyfriend's three college-age sons for the first time.
"Everything was going great until I got here," Allen said outside a Gypsum convenience store. "I guess I'll have leftover turkey. It tastes better anyway."