DENVER — The agency says the slide covered state Highway 91 about 1 mile (1.6 kilometers) south of the Copper Mountain ski area Thursday.
It was at least the third major slide of the day and came after the Colorado Avalanche Information Center warned that avalanche danger was extreme, the highest rating.
The center said heavy March snow combined with strong winds created some of the most dangerous conditions in years.
Another slide near Copper Mountain earlier Thursday ruptured a natural gas line, cutting off gas to a wastewater treatment plant and a gas station.
A slide on Interstate 70 near Vail Pass left 6 feet (2 meters) of snow on the highway, engulfing a tow truck and closing a vital east-west highway. The driver wasn't hurt.
The Arapahoe Basin ski area said it would delay its opening Friday because of avalanche danger. No opening time was announced.
