ELDORADO SPRINGS, Colo. -- Dozens of searchers are combing Eldorado Canyon for a missing climber who fell and hit his head on Tuesday.

He was identified as Lance Hering, 21, of Boulder.

Steve Powers, 20, also of Boulder, said Herring was free climbing on a rock face when he fell, striking his head late Tuesday evening. Powers estimated that Hering fell approximately 10 to 15 feet, but then rolled down a steep slope another 30 feet before coming to a stop. Powers said that Hering was knocked unconscious as a result of the fall.

Powers said he remained with the injured climber until he regained consciousness about four hours later and then left him to summon help. The Sheriff’s Office was notified of the accident at approximately 5:00 a.m. Wednesday.

When rescuers returned to the place where the two spent the night, Hering was gone.

Additional searchers were called in and the search team had about 40 participants, along with four search dogs and a helicopter Wednesday.

Searchers found blood, a water bottle and his hiking shoes, but no other sign of Hering. Hering was last seen wearing a black T-shirt, khaki pants and had a bandage on his head made from a piece of the black T-shirt.

The search area is in the west end of the Eldorado Canyon State Park on a steep trail that goes to Walden Ranch.

Eldorado Canyon is a popular climbing area southwest of Boulder, Colo.

Hering is a U.S. Marine in excellent physical shape. His family said he knows the canyon well.

"He's a very self-sufficient person and it would be like him to hike out and try to take care of his wound," said Lloyd Hering, Lance's father.

Lance's parents said they are worried but remain hopeful.

"He may be sleeping somewhere out there unconscious," said Lance's mother. "They're going to find him."

"Lance, if you are out there, please make yourself known. Don't be embarrassed. Call the Sheriff's Department," said Lloyd.

Lance's parents said he is a risk taker but is a tough young man who just got back from duty in Iraq.

"It's very ironic that he survived all the combat he saw in Iraq and he has now been injured here at home doing what he loves best," said Lloyd.

The canyon is rugged and search crews will be pulled out come nightfall Wednesday. They will keep about half a dozen searchers at key points in case Lance comes out during the night.