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Environment | Land

THIN ICE: Exploring Mount Hood's Glacier Caves

On the slopes of Mount Hood, six explorers set off in a line up the Sandy Glacier.

Eddy Cartaya pulls ahead of the group, a stony expression on his face.




Experience THIN ICE

The Sandy Glacier flows down a steep bowl about two-thirds of the way up Mount Hood’s northwest side. You can see it from Portland; a wedge of snow and ice between two broken ridgelines that rise toward Hood’s 11,250-foot peak.


Glacier Caves
McGregor (L) and Cartaya prepare to enter the moulin. Credit: Katie Campbell


Since then, McGregor and Cartaya have mapped more than a mile of caves and tunnels beneath the Sandy.



Listen to the radio report

In addition to their climbing gear, the team carries survey tools. At the mouth of the moulin, they build anchors in the snow and begin fixing ropes.

“ROCK!” someone calls out.


McGregor ropes up and walks to the edge of the pit.


Cavers rappel down into the moulin. Credit: Andy Maser



He drops out of sight.



A World Beneath The Ice


Watch the animation

Mount Hood Glacier Caves Animation

Credit: Oregon Field Guide



Gulley says it’s hard to say for sure because few people have the skills - or the inclination - to explore a glacier’s plumbing system. Gulley is one of the few. He crawled deep inside glacial caves in Nepal, Alaska, and Svalbard during his field studies.


Moulins and caves are normal features in glaciers. They function as the drainage system for these rivers of ice. Normally, conduits form when temperatures rise and melt water flows down through cracks in the ice. They collapse when the melt season ends. It’s an annual cycle.

Large, permanent caves like those on the Sandy only form when a glacier is thin and the weight of the ice no longer squeezes the caves shut, allowing warm air to flow into the glacier.

The Artist And The Ice Climber



Glacier Caves
Brent McGregor. Credit: Katie Campbell







Glacier Caves
Eddy Cartaya. Credit: Katie Campbell

“It brought the risks more into focus,” Cartaya says. “I used to climb without ropes on ice and rock. Now I’ve stopped doing that.’




The Way In

Over the years, McGregor searched 17 glaciers in Oregon without any luck, rappelling into crevasses and marveling at the snow formations inside. Then in 2011 he found a

video of people inside a cave in the Sandy Glacier.

A thick blanket of fog covered the glacier the weekend he and Cartaya went looking for it. The men spent a day searching for the entrance and found nothing. On the second day, McGregor spotted a deep crack in the ice.


Thin ice in the caves appears blue-green. Credit: Brent McGregor



But they’d never found anything like this before. The cave sucked them in, not only because it of its unique beauty, but because the ice was constantly changing.


Cave Fever



It’s called cave fever, or just the fever.


Inside Snow Dragon. Credit: Brent McGregor

After that, McGregor and Cartaya discovered the moulin together. They named it Cerberus after the three-headed dog that guards the gates to the underworld of Greek mythology.

They kept exploring through the dead of winter. Cartaya remembers thinking that even a minor injury like a sprained ankle could have left one of them dead from hypothermia.


They found a third cave, named Frozen Minotaur, a maze of unstable tunnels filled with rolling rocks and frigid whitewater. They hauled in scuba gear to explore it. At one point, McGregor’s wetsuit came unzipped and immediately inflated with freezing water “like the Michelin Man,” he says. He thought for a moment his heart had stopped. Cartaya dried him out and warmed him up.

Glacier Caving Caution


Glacier cave exploration requires preparation for serious hazards:





Tomorrow: Cave exploration and climate change discovery.


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