Mendenhall Ice Caves

These passages extend through a glacier measuring 12 miles (19 kilometers) in length and display walls of compressed ice ranging from pale aquamarine to deep cobalt depending on density and age of the frozen material.

The formation emerged from what Tlingit people call Sitaantaagu and Aak'wtaaksit, which has withdrawn nearly 2 miles (3 kilometers) since 1958 after retreating only half a mile over the previous 450 years.

Scientists use these formations as research sites to study how glacial systems respond to environmental change and to monitor ice dynamics within temperate rainforest settings.

Reaching the site requires guided excursions combining kayaking to the glacier terminus and ice climbing with specialized equipment, typically available from July through September when conditions permit safe entry into the changing formations.

Meltwater continuously carves new tunnels while existing ones disappear, causing the internal geometry to shift weekly and creating completely different configurations depending on seasonal temperatures and water flow rates throughout the year.

Location: Alaska

GPS coordinates: 58.44234,-134.55591

Latest update: November 27, 2025 21:02