What happened to the Mendenhall ice caves?

For a few years, the Mendenhall ice caves were among the most photographed places in Alaska. Pictures of people standing under ceilings of glowing blue ice spread around the world, and many visitors still arrive in Juneau hoping to find them.

The caves in those photos are gone. Here is what happened, and how you can still see blue glacier ice safely.

How the caves formed

Meltwater runs under and along the sides of the glacier. As it flows, it carves channels through the ice. When the water drains away or changes course, it can leave a hollow tunnel behind. Light filtering through the thinner ice above gives the walls their blue colour.

Why the famous caves disappeared

Glaciers move and melt constantly, and Mendenhall Glacier is retreating quickly. The caves that made headlines melted, collapsed or became unreachable as the ice pulled back. New openings still appear from time to time, but they are short-lived and can collapse without warning.

Why you should not go looking for them

Reaching the side of the glacier means a long, rough hike or crossing the lake, followed by travel over unstable rock and ice. Inside a cave, blocks of ice can fall at any time, especially on warm days. People have been seriously injured and killed by falling ice at Alaskan glaciers.

The US Forest Service warns visitors not to enter ice caves. We agree.

Safer ways to see blue ice

• A guided glacier trek. Guides take you onto the ice with crampons and harnesses, to crevasses and meltwater streams where the blue colour is just as striking.
• A helicopter landing. Short walks on the icefield, with a guide who knows where it is safe to stand.
• A canoe or kayak tour. Icebergs on Mendenhall Lake often show the same deep blue, seen from a safe distance.