Uploaded June 2026 | Updated September 2026, 1 week ago
Just north of Mammoth Lakes, hidden among the volcanic landscape of the Eastern Sierra, sits one of the most unusual geological sites in California: Obsidian Dome.
Formed during a volcanic eruption only a few hundred years ago, Obsidian Dome is a mountain made largely of obsidian, natural volcanic glass created when silica-rich lava cooled rapidly. Walking across its surface feels like stepping onto another planet, with black glassy rock, pumice, and evidence of powerful volcanic forces still visible everywhere.
In this video, we start at Horseshoe Lake, where the ground is killing the forest from below, then head a few miles north to Obsidian Dome. We will see how it formed, and discover why the Mammoth Lakes region remains one of the most geologically active areas in the United States. From lava domes and ancient eruptions to active volcanic systems that continue to shape the landscape today, this is a fascinating look at one of California's youngest volcanic features.
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Just north of Mammoth Lakes, hidden among the volcanic landscape of the Eastern Sierra, sits one of the most unusual geological sites in California: Obsidian Dome.
Formed during a volcanic eruption only a few hundred years ago, Obsidian Dome is a mountain made largely of obsidian, natural volcanic glass created when silica-rich lava cooled rapidly. Walking across its surface feels like stepping onto another planet, with black glassy rock, pumice, and evidence of powerful volcanic forces still visible everywhere.
In this video, we start at Horseshoe Lake, where the ground is killing the forest from below, then head a few miles north to Obsidian Dome. We will see how it formed, and discover why the Mammoth Lakes region remains one of the most geologically active areas in the United States. From lava domes and ancient eruptions to active volcanic systems that continue to shape the landscape today, this is a fascinating look at one of California's youngest volcanic features.
○ Gear we use: amazon.com/shop/sidetrackadventures
►Join us on Patreon: patreon.com/SidetrackAdventures
►Please subscribe for weekly updates showcasing some of our adventures: youtube.com/channel/UCdueDRFYPVgzPAAOM_bxVWA?sub_confirmation=1
►Also please follow Sidetrack Adventures on Instagram: instagram.com/sidetrackadventures
►Music in this video is from Epidemic Sounds; use our link for a free trial: share.epidemicsound.com/v927fj
