Castner Glacier Ice Cave

Full cave from mouth jonwildman74 (Atlas Obscura User)

What could be more awesome and larger than life when standing in the face of a gigantic wall of ice? In the winter, you can enter the blue ice cave. In the summer, a rushing creek pours out of the cave. No matter the season, this place offers an adventure.

In the early summer, the amount of water pouring out of the glacier’s cave entrance can be staggering. The melting ice creates a roaring creek the color of chocolate milk that, at times, can feel like it slightly shakes the ground. In areas where the water slows down, you can watch the silt settle out of the water. It leaves behind crystal clear water if only for a monument… Then another wave of the chocolatey water surges forth. In the shallow pools of creek water, the silt can act like quicksand, and you will quickly sink.

While standing on the massive piles of rock debris from the glacier, you must be on the lookout for falling rocks. Just above the cave entrance is the roof of the glacier. As the ice melts, debris is dislodged and will roll down the steep face toward the ground, resulting in a constant rain of rocks, pebbles, dirt, mud, and sometimes large rocks.

In 2024, the Bureau of Land Management proposed a new plan that would place limits on recreation around Castner Glacier in order to protect the landscape.

Know Before You Go

The parking area for the hike to the actual glacier is not labeled. The GPS location is 63.403953, -145.735397. This is on the north side of Castner Creek when facing the glacier. There is more parking on the south side of the creek when facing the glacier at GPS location 63.40238, -145.73466.

The easiest and best way to ensure your hike to and from the glacier cave is successful is to follow the creek. Follow on the north side of the creek when facing towards the glacier. Do not hike on the south side of the creek—you will have to cross the river, and in the summer it will be impossible.

In the summer, be aware that any GPS locations here for the mouth of the glacier cave are subject to change at any point because it is always melting.

In the winter, prepare for hiking in cold temperatures and difficult terrain.