Crowley Lake Columns

Useful Information

Location: Between Bishop and Mono Lake. At Crowley Lake, east shore.
Leave Hwy 395 at Toms Place. Follow Owens Gorge Road to the dam. On the other side of the dam single lane dirt track. Track requires 4WD, may be too bad even for this, then you have to walk.
Alternatively hire a boat.
Open: no restrictions.
Fee: free.
Classification: Speleologyerosional cave
Light: bring torch
Guided tours: n/a
Photography: allowed
Accessibility: no
Bibliography: Noah Randolph-Flagg, Stephen Breen, Andres Hernandez, Michael Manga, Stephen Self (2017): Evenly spaced columns in the Bishop Tuff (California, USA) as relicts of hydrothermal cooling, GEOLOGY, Volume 45, Number 11, Geological Society of America. doi:10.1130/G39256.1. online
As far as we know this information was accurate when it was published (see years in brackets), but may have changed since then.
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1941 Crowley Lake reservoir completed.


The Crowley Lake Columns are named after the nearby artificial lake, which is also responsible for their existence. This cave system is formed by the waves of the lake. Unfortunately the lake is also the reason why they are often not accessible, as the rising water of the lake may flood them mostly. But even if they are accessible, which is an quite easy walk along the lake shore, they are nevertheless hard to reach. It is necessary to leave the paved road, follow a single lane road to the dam and cross it, and on the other side a quite bad mud track follows which requires a 4WD, Depending on the situation and recent rains a passage might be impossible. In this case its a 7 km hike through the desert. Make sure to check the level of the lake before, so you are actually able to see the caves after your hike.

The area is of volcanic origin, the caves are ersional caves formed by the rosion of the artificial Crowley Lake, so they are very young. Here at this place a thick layer of soft tufa, which is eroded quickly, contains pillars of harder rocks, which form the "columns" of Crowley Lake Columns. The result is actually a single huge chamber where the soft rock is removed and the hard pillars support the ceiling.

A study at UC Berkeley determined that the columns were created by an eruption 760,000 years ago. It was 2,000 times larger than the 1980 eruption of Mt. St. Helens and created the Long Valley Caldera. The thick layer of pumice and ash was another result. Cold water percolated down into the ash, was heated, and steam rised up again. This hydrothermal convection caused a recrystallization and hardening of the soft ash around its path, which created the columns. The convection cells were evenly spaced, similar to heat pipes. The tufa with the pillars inside covers an area 3 km by 5 km, and there are approximatel 5,000 columns. They are visible at all places where the lake shore eroded the tufa.