Fred Gallant, 33, clung to a rock for two and a half hours as the frigid water tumbled past him. He was finally rescued by a U.S. Coast Guard helicopter crew.
Gallant and co-worker Jerome Abbot were in a skiff when Abbot lost control of the boat.
The men were moving swiftly toward the falls, but Abbot was able to get out of the boat and make it to shore.
Gallant's foot snagged on the skiff, and he fell into the water wearing a flotation vest and chest waders. His waders filled with water and dragged him under the surface.
He came up beside the boat at the bottom of one waterfall and the top of another, but managed to hold on to the boat, which was snagged precariously on rocks.
"I just held on," he said. "There was no way I could put my total weight on the boat or we both would have gone over."
Tourists nearby called for help for Gallant.
"I'm a pretty big guy," he said, "and I'm Tlingit, so pretty hot-blooded. And I'm disciplined and I can persevere. I have two beautiful children at home and a community that supports what I do, so there's a lot to come home to."
--The Associated Press