Singletrack/MTB
Gravel/All-road
Dirt-road Touring
Fat-bike
Basin & Batholith: Two Days in a Volcanic World (Video)
Leigh Foster’s latest “Loop of Loops” series video follows him along the Basin and Batholith route into the Long Valley Caldera, around a frost-covered ancient Mono Lake, among the chaos of Obsidian Dome, and into a surprise snowstorm on the way back to Mammoth. Watch the video showcasing these quiet miles and find a trip report here…
Words, video, and stills by Leigh Foster
Mammoth is a ski town, but when I arrived, it was almost empty. The lifts were still. The shops were quiet. The crowds were a week away. It was the perfect opportunity to see the place before the noise—and to begin the next loop in my Loop of Loops project, where I ride BIKEPACKING.com routes across the American West and make a film about each one. Watch it below, and read on for more thoughts on the trip.
I pedaled out of town and dropped into a 20-mile-wide bowl left behind by one of the largest eruptions Earth has ever seen, the Long Valley Caldera. The magma chamber emptied so quickly and completely that the ground collapsed more than 100 feet, creating the basin that exists today. Ash from the blast reached as far away as Nebraska. Now it looks calm—just sagebrush and open sky—but the ground is still venting heat beneath my tires. That heat shows itself at Hot Creek, where boiling water forces its way through fractures in the canyon floor. Steam, sulfur, and streaks of bright mineral color mark a landscape that’s still very much alive. From there, the route begins to climb.
By evening, I’d crossed over the mountains and made camp above Mono Lake. Even from up here, I could already tell it was no ordinary place. When the sun dropped, the temperature followed. I woke to frost on my gear and rode down to the shoreline to make a cup of coffee. Mono Lake is nearly a million years old—one of the oldest lakes on the continent. Its water is so salty and alkaline that it supports brine shrimp and clouds of alkali flies in numbers you can’t quite believe. Towers of calcium carbonate rise from the shallows. It’s a remnant of the ancient inland sea that once filled this region, one of the last of its kind.
The route continues across sand and sage before bending back up into the mountains. The wind picked up as the storm closed in. Near sunset, I left the bike and hiked into Obsidian Dome, a massive pile of volcanic glass that surfaced only a few hundred years ago—yesterday in geologic time. Sharp slabs of stone stretching in every direction, and the strangely satisfying sound of pumice crunching underfoot. It’s a landscape that feels almost extraterrestrial.
When the snow arrived, it came fast. One minute it was wind; the next it was winter. I stood there in the trees, watching the season change right in front of me. Then I got back on the bike and rode toward town as the mountains disappeared behind a curtain of white.
The Basin and Batholith is an overnight bikepacking route set in the heart of the Eastern Sierra. The route traverses the Long Valley Caldera and many of its geologic wonders, from the ecological marvel of Mono Lake to the youngest mountains in North America. Beyond pedaling stunning trails, it affords an opportunity to soak in hot springs and stargaze through the silhouette of the surrounding peaks. Find the full route guide here.
Further Reading
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