Crowley Lake Stone Columns

The Crowley Lake Stone Columns, tucked along the eastern shoreline of Crowley Lake south of Mammoth Lakes, are a collection of thousands of strange, cathedral-like pillars and archways, some reaching roughly 15 to 20 feet tall. They formed 760,000 years ago following the massive Long Valley Caldera eruption, when cold groundwater and snowmelt seeped into still-hot layers of volcanic ash. As that water heated and rose back up as steam, minerals precipitated along the vertical flow paths, cementing the ash into harder, erosion-resistant columns. Much later, erosion along the shoreline, particularly after Crowley Lake was created as a reservoir in 1941, stripped away the softer surrounding material, exposing the formations seen today.