BOULDER, Colo. -- It was a hike that Carl Cox will never forget.

"The wind was howling. It was pretty cold."

Cox and his good friend, Bill Hudson, were hiking Tuesday on Sandbeach Trail in Rocky Mountain National Park.

They had been to the park numerous times in all kinds of weather.

"It's beautiful," Cox said. "You can hike up to the Continental Divide and look at beautiful territory. It's a good feeling."

Cox said he, and Hudson, both 68, hiked and skied regulary to stay in shape and to keep their cholesterol in check.

But this trip wasn't like any of the others.

They were on their way back to the trailhead when a 50-foot douglas fir snapped, and fell on them.

"I heard a noise," Cox said. "I just hollered 'tree fall.'"

Park spokesman Larry Frederick said William Hudson and Carl Cox, both 68, were hiking up the Sandbeach Lake Trailhead when "a dead Douglas fir tree, approximately 30 feet from the trail, broke off 15 feet above ground striking both."

Cox said he lunged to get out of the way.

"I was instantaneously hit with something on my back."

The tree, felled by high winds, knocked Cox on his face. He said he laid there for several seconds, then called for Bill.

He got no response, so he pulled himself up and noticed Bill lying a few feet away.

"I looked at him for five seconds and said, 'I think he's dead.' His eyes were open and not moving. I kept calling and did that (patted his face) to him, tried to find a pulse."

Cox said Bill's head was resting on a big rock.

Cox knew he had to get help, so he started hiking down by himself. About a mile from the trailhead, he saw lights at a maintenance shop. A forest service employee working inside helped him call emergency crews. They recovered Hudson's body late Tuesday.

"It's absolutely astounding," said Hudson's longtime friend, Unviersity of Colorado math professor Martin Walter, "because Bill was the most meticulous and careful person in every aspect of his life."

Walter said Hudson was a mathmetician whose specialty was probability.

"He said the last time he was in the park, there were a lot of downed trees. He said (during one hike) a tree fell over about 20 feet from where he was, so he was well aware of the danger. That made it more improbable that one would get him," Walter said.

Walter had known Hudson since 1966. Hudson was the best man in his wedding.

"He was trustworthy," Walter said. "You could bet your life on the guy. He'd always be there for you, if you needed him for anything. Friends like that are hard to come by."

"I'd say he was a gentle person," Cox said.

When asked about his own injuries, Cox replied, "Compared to what happened to Bill, I'm not even worth talking about. I'm just darn lucky."

Cox injured his back, and is being fitted with a brace to help stretch a compressed disk.

He said once his back is fixed, he plans to resume hiking. When he does, he said he'll be thinking about his friend.

"One of the guys asked me if I think they ought to shut down the trail," Cox said. "I told him I thought that was nonsense. I think Bill would feel the same way."

Wednesday morning, rangers got a better look at the tree and brought out a section of the tree for analysis. The 50-foot Douglas fir is believed to have died five to 10 years ago, Frederick said.

Strong winds were reported in the area when the tree fell, officials said. Rangers say the chances of being hit by a falling tree are as likely as being hit by a bolt of lightning.

"There is always inherit risk when you are going to the wilderness, and that's one of them," said Jim Sandborg, a forester for RMNP.

However officials said they do what they can to make trails safe for hikers.

"We cut trees in trailheads and around structures and facilities and parking lots and things to mitigate those types of hazards," said biologist Brian Verhulst.

Verhulst and two other foresters from RMNP removed part of the fallen tree Wednesday for study.

There was speculation the tree was killed by the pine beetle outbreak found throughout the Rocky Mountains.

Forester Patty Shafer said this particular tree was not infected with the infestation, but did say trees killed by the pine beetles do pose a risk to hikers.

"You look around this trail, there's dead trees everywhere along the trail. It's not something we can control," Shafer said.