Kealii Mamala and Garrett McNamara: partners in glacier surfing | Photo: The Glacier Project

Garrett McNamara and his longtime friend Kealii Mamala love to chase challenges. Frequently, these challenges involve water and waves located in unusual spots. In 2013, they rode glacier waves.

It was cold out there. The water temperatures gave a new meaning to cold water surfing, but the Hawaiian duo didn't care. They wanted to ride the glacier tsunami; they wanted to be the first to ride a wave created by a breaking mountain of ice.

Risks are high, but the thrill of surfing the Child's Glacier, near Cordova in Alaska, is bigger than life. They're professional risk managers, and they've been doing these dangerous stunts in the last couple of decades.

They had to wait for Nature. When the ice falls and crashes into the water, McNamara and Mamala get set. There aren't many waves, so the moment the glacier generates the first tsunami waves, they ride it.

"It was the heaviest thing I've ever done in my life! It's like the Empire State Building about to come down on top of you. It was the closest I've ever come to death," explained Garrett McNamara.

"I was up to my neck in water, looking up at this 90-meter tall glacier, waiting for the ice to break off and hoping that it'll fall straight into the water - because if it falls flat you'll be squashed under it."

Can you imagine looking up and watching a 300-foot glacier breaking into pieces right in front of you, and then having to surf its powerful waves?

Garrett McNamara and Kealii Mamala camped for three weeks near the Child's Glacier and had to spend up to 20 hours in the water a day waiting for the critical minute. History was in the making.