, Auditorium
Mount Baker, Washington, USA (Kollia-Kulshan in the language of the Nooksack), hosts a significant glaciovolcanic cave system which was first investigated by Eugene Kiver and his team from 1974-1978. At that time, a large thermal pulse and gas emissions had caused ice melt and the expansion of cave passages in the glacier ice of Sherman Crater. At the time, the cave system was reportedly ~1200 m long, but it had not received modern investigations or surveys. A reconnaissance trip in 2024 by a subset of our team noted several cave entrances in Sherman Crater connected to a significant glaciovolcanic cave with passage diameters of up to 10 m. Given the intensity of fumaroles and the presence of sulphureous gases in the crater, expedition members likened the landscape to that of Utumno and Mordor from Tolkien's Middle Earth. The resulting Mount Baker Glaciovolcanic Caves Project expedition in September 2025, was conducted by a team of experienced cavers and researchers and supported by dozens of porters for mobilization and demobilization. Team members used Air Purifying Respirator (APR) mask systems with acid gas filter cartridges to protect against H2S throughout the subglacial environment and at the entrances. The resulting survey and observations revealed a vast and dynamic cave system over 1500 m long, driven by fumarole emissions and hot englacial streams. Integrated microbiology and geochemistry research complemented the expedition, which has revealed one of the longest and deepest glaciovolcanic caves in the world.
Christian Stenner, Royal Canadian Geographical Society,
Alberta Speleological Society
Lee J. Florea – Washington Geological Survey,
Bloomington Indiana Grotto, & Oregon Grotto