Authorities say two people are dead after a Black Hawk helicopter from Fort Campbell in Kentucky crashed into the side of the Colorado's second-highest mountain.

Lake County Sheriff spokesman Max Duarte says one person was flown to a Denver hospital and rescue teams are looking for a fourth passenger who is missing. Duarte says two people died in the crash but he didn't have any information about the people on board.

Duarte says helicopter was from Fort Campbell and was practicing in the central Colorado mountains. He did not know how long they had been flying around Mount Massive, which is 14,200-feet tall.

Officials say the crash happened at about 2 p.m. Wednesday. U.S. Forest Service workers building trails with a youth group heard the crash but didn't see it.