Hot Spring On Umnak Island
This Aleutian hot spring produces water at an impressive 149 degrees Fahrenheit, creating one of the hottest documented thermal features in the Aleutian chain. High dissolved salts with 1,300 mg/L chloride and other minerals characterize its geothermal chemistry. It sits at just 100 feet elevation approximately 29 miles from the nearest road on an island with active volcanoes.
The spring flows on Umnak Island at 100 feet elevation in a coastal volcanic landscape. The water emerges mineralized and steaming with temperatures that create a distinctive thermal environment. The island hosts several active volcanoes including Mount Okmok, which erupted in recent years, shaping the dramatic landscape around the spring. The terrain features volcanic cones, lava flows, and active geothermal manifestations.
This hot spring formed through vigorous geothermal activity on Umnak Island, where active volcanoes including Mount Okmok demonstrate ongoing geological activity. The spring's high temperature and mineral content reflect a robust geothermal system derived from proximity to active volcanic heat sources. The island sits in a region where subduction zone volcanism drives continued thermal activity and periodic eruptions.
Access requires backcountry travel and boat access to the island, approximately 29 miles from Beachmaster Street. The spring sits in extreme isolation with no nearby facilities or developed infrastructure. Average annual air temperature reaches 39.6°F with 52 inches of precipitation and 92 inches of snow. Visitors should expect challenging maritime weather and must be completely self-sufficient.
Is Hot Spring On Umnak Island worth visiting?
Best for
- Observing powerful hot springs
- Backpacking adventures
- Winter soaking with dramatic temperature contrast
Not ideal for
- Casual soaking
- Day trips with young children