Before he realized what was happening, Brown was swept up in the current and sent plunging more than nine stories down a rushing waterfall. Still alive, he is recovering from his injuries in Portland, Ore.
The young gymnast The Early Show co-anchor Hannah Storm, his story:
"Well, the lava canyon is a really extreme place. It was carved out of mountain sides by the Mount Saint Helen's eruption, so there's jagged rocks and there's water falls all over the place.
"What happened was, I tried to jump over this really narrow section of stream about three feet wide and it seemed so easy," he explained. "All I did was jump across. I have jumped across things that were more than twice that far before. But for some reason I just slipped in and the current carried me away.
"There was no way I could get out too, because the size of the rocks, were so slippery. I floated past my brother as I went by, because I was in the water for about 20 feet before I actually went down the waterfall. He saw me, but he was too far away to help me in time. He just saw me reaching for things. Then I went down."
Brown tumbled down a 65-foot waterfall and then was swept down another 25-foot drop.
He said, "The strange thing was, I never lost consciousness. But my perception of time sort of changed. It was as if time slowed down and everything got blurred even before I got hurt. I remember falling down the first 65 feet and hitting a ledge. They say it's two waterfalls but I would call it just one because they're really close together. The second waterfall is just a ledge that's sticking out of the side of the mountain. But anyways, I fell down the first 65 feet and then I don't remember feeling surprised or shocked or fear or anything. I just remember hitting the rock with my back.
"Then I fell another 20 feet and I hit another rock. And then I rolled off into the stream. And then I was rolling around in the water for a few seconds until I got to some more shallow water. I pulled myself on to a rock and I sat there."
Fifteen minutes later, two of his friends were with him after running about three miles down the mountain. They supported him and carried him to the side of the river, where they awaited paramedics. A helicopter took him to the hospital, he said.
Brown suffered a broken ankle, gashes on his head and a splintered vertebra. He will have to have surgery on his ankle.
A gymnast by trade, Brown said, "I would attribute my survival mostly to gymnastics because I have been in it for the last three years and the training that they put you through is really intense. I'm in really good shape and I'm really limber.
"I think that even though I wasn't thinking about where to put my hands and I wasn't thinking about actually saving myself, I unconsciously knew the best way to fall down in order to save my life."