Stephen Hansen, 14, couldn't see the boy being carried past Sandy Beach by the Gastineau Channel current late Monday night, but he could hear his desperate cries for help in the dark.
The boy, 12, who was picked up by rescuers, was treated at Bartlett Regional Hospital for mild hypothermia and was home by midnight in good condition, hospital officials said.
Hansen, a camper at Sandy Beach on Douglas Island, said he called police around 10:45 p.m. to report a young boy had jumped into the channel and was drowning.
"I got really scared," Hansen said today. "When I was calling his name - it just took so long for him to answer me. He kept saying, 'Help, I'm drowning,' and, 'I'm so cold. It's so cold.' I had my shorts on, ready to dive in, but there was no point. I couldn't even see him. I could only hear him yelling."
Coast Guard Petty Officer David Foucault said Coast Guard rescue swimmers, Juneau police and Capital City Fire and Rescue personnel rescued the boy shortly after 11 p.m.
The boy, whose name was not released, and two other boys, age 15 and 17, had climbed into the abandoned pump station on the beach to build a fire and keep warm, police said. Hansen said he and two of his friends also were on the beach camping and had been talking with the other group of boys.
The fire in the station caused a small explosion, Hansen said the boys told him. With the tide coming in and surrounding the station, a relic from the long-closed Treadwell Mine, the beach campers told the boys to jump in the channel and swim to shore, Hansen said.
The older boys jumped into the water with the 12-year-old following shortly behind them.
"The two older boys made it to shore, but then one of them said to call the police that the younger one was drowning," Hansen said.
The boys on shore saw the 12-year-old floating with the current of the channel, but quickly lost sight of him. Rescuers found the boy, going in and out of consciousness, clinging to a wooden piling, the Coast Guard said.