Mystery Of Crowley Lake Columns Solved

After California’s Crowley Lake reservoir was completed in 1941, strange column-like formations were spotted on the water body’s eastern shore. The rising gray and stony cylinders have cracks ringing around them at intervals of about 1 foot and have inspired comparisons to Moorish temples.

With those sort of descriptions out there, it’s not surprising that theories on the origins of the columns have been similarly wide-ranging. Some believed they were just portions of rock that, as luck would have it, were eroded away to form the perfect, rising spirals and arches. Others believed the columns had a connection to the area’s volcanic past.

Crowley Lake columns. (Credit: Sierra Adventure Center)

To get at these questions, geologists at the University of California, Berkeley, set out to investigate. Using a slew of different methods and equipment, including X-ray analysis and electronic microscopes, applied to samples of the columns, the researchers have found there are tiny spaces throughout them.

These are cemented into place by minerals that are resistant to erosion, and appear to be related to a large volcanic explosion that took place about 760,000 years ago. Scientists say that the blast was more than 2,000 times larger than that of the eruption of Mount Saint Helens, and created the Long Valley Caldera that holds the Crowley reservoir today.

The Mammoth Lakes region in California. (Credit: Wikimedia Commons User Tyersak via Public Domain)

In describing the formation of the columns, researchers believe that falling snow melted on top of the tuff rock deposits left after the eruption. This still-heated porous material caused the melted snow to boil, which created the even spaces between the columns that exist today.

Estimates hold that there are up to 5,000 of the columns within a 2- to 3-square-mile area to the east of Crowley Lake. They appear in clusters of varying shapes and sizes. Some are gray and as straight as poles, while others are reddish-orange and bent or tilting. There are also still-buried columns that would look like fossils to an untrained eye.