Five snowboarders were killed Saturday afternoon after apparently triggering a backcountry avalanche on Colorado's Loveland Pass, authorities said.
Search and rescue crews recovered the bodies several hours after the slide, which was about 600 feet wide and eight feet deep, said Clear Creek County Sheriff Don Krueger.
A sixth snowboarder caught in the avalanche was able to dig himself out and call for help, Krueger said. That person's condition wasn't immediately known.
The victims all had avalanche beacons, Krueger added.
The Colorado Department of Transportation closed U.S. 6, which crosses the Continental Divide near the scene of the avalanche, to facilitate the search. The pass is heavily traveled by skiers visiting nearby Arapahoe Basin ski resort.
The bodies were taken to the Clear Creek coroner's office. The victims' identities weren't immediately known.
Krueger said authorities were "pretty sure" the snowboarders triggered the avalanche, which he said traveled about 1,100 feet some 100 yards off U.S. 6.
The avalanche occurred on a spring weekend when many skiers and snowboarders took advantage of late season snowfall in the Rocky Mountains. At least four Colorado ski resorts reopened for the weekend after a snowstorm earlier in the week, and four others were still open for the season.
Loveland Pass, at an elevation of 11,990 feet, is popular among backcountry skiers and snowboarders, and on Saturday, Snowboard Magazine had promoted the Rocky Mountain High Backcountry Gathering there for a day of gear demonstrations and shredding.
Treacherous winter weather is not unusual on the pass, which is about 60 miles west of Denver. Skiers and snowboarders in search of fresh snow often hitchhike from lower elevations to the rocky summit above tree line. The area also is popular among photographers and tourists seeking some of the most expansive views in Colorado.
Colorado Avalanche Information Center forecaster Spencer Logan said there have been weak layers in Colorado's snowpack since early January.
"Our last series of storms made them more active again," he said. "Over the last week and a half, that area got over 18 inches of snow, so if you melted that that would be 2 inches of water, so that is a heavy load."
Lisa Clarke Devore, who was headed back to Denver from the resort, told The Associated Press she saw a fire truck and ambulance on the pass, as well two search dogs headed into the area of the slide. She said she saw several ambulances, including one towing snowmobiles, driving toward the pass.
On Thursday, a 38-year-old snowboarder died in an avalanche south of Colorado's Vail Pass. Eagle County sheriff's officials said the man and another snowboarder likely triggered the slide after a friend on a snowmobile dropped them off at the top of Avalanche Bowl.
U.S. avalanche deaths climbed steeply after 1990, averaging 24 a year, as new gear became available for backcountry travel. Until then, avalanches rarely claimed more than a handful of lives each season in records going back to 1950.
Associated Press writer Thomas Peipert in Denver contributed to this report.