(New throughout, adds details on three survivors)
DENVER, Jan 7 (Reuters) - A large avalanche in backcountry outside the Colorado ski resort area of Vail killed a person on Tuesday and caught up three other people who survived and were being rescued, county officials said.
Rescuers were working to pull the three victims off the mountainside, the Eagle County Sheriff's Office said in a statement. It said none of the injuries were life-threatening.
The avalanche occurred in the East Vail Chutes in an area that Eagle County spokeswoman Kris Friel said was beyond the boundary of the Vail ski resort, one of the largest and most well known in North America. Vail is about 75 miles (121 km) west of Denver.
The fatality was a man, according to television station KUSA, an NBC affiliate.
Officials did not immediately say what activity the four people were engaged in when they were caught in the avalanche,
The Colorado Avalanche Information Center said in a post on Twitter that the avalanche was large and occurred near a tree line on a slope.
The avalanche comes less than a year after five backcountry snowboarders were killed in an avalanche in April 2013 at Colorado's Loveland Pass, 48 miles (77 km) west of Denver.
The avalanche danger in the Vail area on Tuesday was rated as "considerable," due to high winds and recent heavy snows, said Spencer Logan, forecaster with the Colorado Avalanche Information Center.
This avalanche death was the second such Colorado fatality this winter season, and the fifth nationwide, Logan said. (Reporting by Keith Coffman, writing by Alex Dobuzinskis; editing by Cynthia Johnston, Marguerita Choy, Jonathan Oatis and David Gregorio)