GLENWOOD SPRINGS, Colo. (AP) -- Drivers on a heavily used highway in western Colorado are being rerouted about 140 miles out of their way after boulders the size of cars crashed onto the roadway in a deep and narrow canyon, damaging a tractor-trailer, stranding travelers and interrupting regional bus service.
No one was injured Monday night when the rocks tumbled onto Interstate 70 about 125 miles east of the Utah border, but the slide could cause headaches through Thursday afternoon, when crews are expected to clear the way.
The Colorado Department of Transportation shut down traffic in both directions along 24 miles of highway, from Glenwood Springs in the west to Gypsum in the east.
"There is a lot of debris still up on the slope, which remains unstable," CDOT spokeswoman Tracy Trulove said Tuesday. "We had our geologists up there all day, and there's just a lot of loose rock."
Traffic is expected to move slowly even after crews clear the interstate because pilot vehicles will lead drivers through the most damaged areas, the Glenwood Springs Post Independent reported.
Trulove said at least a dozen boulders fell onto the westbound lanes, "the largest about the size of my Dodge Durango."
Ron Milhorn, news director of KMTS radio in Glenwood Springs, who came upon the scene after the slide, said a boulder the size of a small car crashed into a tractor-trailer.
The truck driver, Ray Hatch of Las Vegas, told Milhorn he saw the car in front of him disappear into a cloud of dust before his truck hit a boulder head-on. Hatch was calm and in good spirits after the crash, Milhorn told The Associated Press.
Vehicles that could turn around were escorted back out of the canyon, he said.
The Post Independent reported that downtown businesses saw an increase in customers Tuesday morning as people began making their way toward eastbound I-70 only to realize it was closed. The Ramada Inn also reported an unusually high number of guests Monday night because motorists did not want to drive the winding, two-lane detour route.
"We had a lot of walk-ins last night and again today because of the closure," Tammy Ott, front desk manager at the Ramada, told the newspaper. "It's great for business, sure, but it's tough on the customers."
Meanwhile, CDOT's regional bus that travels from Glenwood Springs to Denver and back each day, picked up only as far west as Vail on Tuesday morning. The westbound return bus stopped in Vail for the night Monday and took the detour to bring passengers back to Glenwood Springs.
Nick Isenberg, of Glenwood Springs, was on the bus and said the 14 passengers spent Monday night at a chapel in Vail. Police made a grocery run to buy milk for a toddler who was among the passengers, Isenberg said, and CDOT provided riders with breakfast.
Average daily traffic through the canyon is about 300 vehicles per hour, according to CDOT. The shortest detour adds about 140 miles to the trip, taking traffic north to U.S. 40 and then back south to I-70.
The Colorado River carved the scenic canyon, which is popular with anglers and rafters. The chasm is so narrow that one 12-mile section of the interstate runs through three tunnels and across 40 viaducts and bridges. It took 12 years to complete.