Mystery Of Crowley Lake Columns Solved

Crowley Lake Columns, also known as the Crowley Lake Columns Tuff or the Columns of the Giants, is a geological formation located near Crowley Lake in the Eastern Sierra region of California, USA.

The Crowley Lake Columns are a group of unusual geological formations located on the eastern shore of Crowley Lake in Mono County, California. The columns are up to 20 feet tall and connected by high arches, and they have been compared to the ruins of an ancient Moorish temple.

They had been buried and hidden for eons until the reservoir's pounding waves began carving out the softer material at the base of cliffs of pumice and ash.

Crowley Lake Columns

In the ensuing decades, the columns were regarded as little more than curiosities along the eastern shore of the Los Angeles Department of Water and Power reservoir, which is best known as a trout fishing hot spot about 10 miles south of Mammoth Lakes.    

Crowley Lake columns.
Crowley Lake Columns – Mono County, California

But now answers are emerging from a study at UC Berkeley. Researchers have determined that the columns were created by cold water percolating down into — and steam rising up out of — hot volcanic ash spewed by a cataclysmic explosion 760,000 years ago.

Mystery Of Crowley Lake Columns Solved
Crowley Lake Columns – Mono County, California

"These columns are spectacular products of a natural experiment in the physics of hydrothermal convection," Noah Randolph-Flagg, 25, a PhD candidate and lead author of the study, said in an interview.

The blast, 2,000 times larger than the 1980 eruption of Mt. St. Helens, created the Long Valley Caldera, a massive 10-by-2-mile sink that includes the Mammoth Lakes area. It also covered much of the eastern Sierra Nevada range with a coarse volcanic tuff, or ash fall.

Randolph-Flagg said researchers not only discovered the origin of the columns but also learned a great deal about the surrounding landscape. "They have lot to tell us about what the region was like before and after the caldera exploded, and about how volcanoes can change local climate," he said.

The columns began forming as snowmelt seeped into the still hot tuff. The water boiled, creating "evenly spaced convection cells similar to heat pipes," according to the study to be presented next month in San Francisco at an American Geophysical Union meeting, the world's largest conference in geophysical sciences.

Analyses by X-rays and electronic microscopes of samples of the columns found that tiny spaces in these convection pipes were cemented into place by erosion-resistant minerals.

Crowley Lake columns.
Section of lake with column formations

Randolph-Flagg estimates that as many as 5,000 columns exist within a 2- to 3-square-mile area east of the lake. They appear in clusters, and are diverse in size and shape.

Many are gray, straight as telephone poles and encircled with horizontal cracks about 12 inches apart. Some are reddish-orange in color. Some are bent, or all tilting at the same angle. Still others are half-buried and resemble the fossilized backbones of dinosaurs.

Next year, the Department of Water and Power will begin ferrying students to the site as part of an "effort to further educate the public about these invaluable natural resources," said Amanda Parsons, a spokeswoman for the utility.

A photo of the Crowley Lake Columns with a person standing in front of them for scale.
Section of the Crowley Lake with column formations

Edward W. Hildreth, a research geologist with the U.S. Geological Survey and expert on the history of the Long Valley Caldera and the chemistry of its tuff, welcomes the sudden interest in the columns, which can be reached by boat, on foot or by four-wheel-drive vehicles.

More analysis could help scientists better understand how quickly the columns solidified, and the chemistry and temperatures that produced their spacing, width, height and composition.

Among other researchers investigating the columns is Robin Wham, 62, a graduate student in geology at Cal State Sacramento whose proposed thesis involves mapping their precise locations and comparing their characteristics to those of similar formations in New Mexico and Mexico.

Crowley Lake Columns – Mono County, California
Section of Crowley Lake with column formations

How the Crowley Lake Columns Were Formed

The Crowley Lake Columns were formed by a process called columnar jointing. Columnar jointing is a type of rock fracture that occurs when a rock cools or contracts. As the rock cools, it shrinks. This shrinkage creates stresses in the rock, which can cause it to crack. The cracks typically form in a hexagonal pattern, which is why the Crowley Lake Columns are shaped like columns.

The exact mechanism of columnar jointing is not fully understood, but it is thought to be caused by a combination of factors, including the rate of cooling, the composition of the rock, and the presence of fluids. In the case of the Crowley Lake Columns, the rapid cooling of the rhyolite ash was likely the primary factor that caused the columnar jointing.


  1. About 760,000 years ago, the Long Valley caldera erupted. The eruption spewed ash and pumice over a wide area, and the ash eventually settled and solidified.
  2. The ash was composed of rhyolite, a type of volcanic rock that is rich in silica. Rhyolite is a good conductor of heat, so it cools rapidly.
  3. As the rhyolite ash cooled, it shrank. This shrinkage created stresses in the rock, which caused it to crack.
  4. The cracks typically formed in a hexagonal pattern because this is the most efficient way for the rock to break.
  5. The cracks were then filled with minerals, which cemented them together.
  6. Over time, the ash was eroded away, leaving the columnar jointed rock formations exposed.

The Crowley Lake Columns,  Mono County, California formed by erosion over millions of years.
Crowley Lake Columns – Mono County, California

How to get to the Crowley Lake Columns

The Crowley Lake Columns are located on the east side of Crowley Lake, about 10 miles south of Mammoth Lakes, California. The best way to get there is to take Highway 395 to Rock Creek. Turn left onto Rock Creek Road and follow it for about 2 miles to the trailhead. The hike to the columns is about 0.5 miles long and moderately difficult.

Facts about the Crowley Lake Columns

  • The columns are thought to be the result of a process called columnar jointing. Columnar jointing is a type of rock weathering that occurs when a rock is subjected to rapid cooling. The cooling causes the rock to shrink, and this shrinkage creates cracks that form columns.
  • The columns are typically hexagonal in shape, but they can also be pentagonal or square.
  • The columns are found in a variety of colors, including gray, red, and orange.
  • The columns are relatively fragile and can be easily damaged.
  • The columns are estimated to be about 5,000 in number.
  • They range in height from a few feet to 20 feet.
  • The columns are made of rhyolite, a type of volcanic rock that is rich in silica.
  • The columns are arranged in a hexagonal pattern.
  • The columns were formed about 760,000 years ago.
  • The columns were not discovered until 1941.
  • The Crowley Lake Columns are a popular tourist destination. They can be reached by hiking trail from the shore of Crowley Lake.

Inside Lake Crowley columns (interior)
Lake Crowley columns - Interior

Visitors interested in geology, natural formations, and photography often find the Crowley Lake Columns to be a captivating destination, showcasing the beauty and intricacies of volcanic geological processes.

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