What Are Hoodoos? The Science Behind These Surreal Formations

Sentinel-like hoodoos of Goblin Valley State Park in Utah. (Photo: IrinaK/Shutterstock)
Hoodoos are a common sight in the western United States. This particular cluster is found in southern Utah's Arches National Park. (Photo: Zack Frank/Shutterstock)

Hoodoos. Fairy chimneys. Earth pyramids. Tent rocks. They have many different names, but these strange badland rock formations are one and the same, and they can be found in various iterations across the planet.

One of the best places to see hoodoos is in southern Utah's Bryce Canyon National Park (pictured below), which boasts a vibrant collection of natural "amphitheaters" filled with craggy columns composed of sedimentary rocks like sandstone and shale.

A natural amphitheater of hoodoos in Bryce Canyon National Park. (Photo: ozoptimist/Shutterstock)

These strange geological wonders are formed over many centuries through a combination of physical and chemical weathering forces. This includes erosion through wind and acid rain, but the most powerful process that helps sculpt these formations is frost wedging.

As the National Park Service explains, "in the winter, melting snow, in the form of water, seeps into the cracks and freezes at night. When water freezes it expands by almost 10 percent, bit by bit prying open cracks, making them ever wider, in the same way a pothole forms in a paved road."

The diagram below gives a visual explanation of how hoodoos are created over an extended period of time:

A visual depiction of how hoodoos are formed over time. (Photo: Brian B. Roanhorse/National Park Service)

As the illustration shows, we start with an intact plateau (1), which is gradually broken down into a rock formation known as a fin (2). The fin then erodes even more to form large gaps and window-like arches (3). As weathering forces continue to wear away at the sedimentary rock, we are left with the wonky standalone columns we know as hoodoos (4).

Of course, there's a fifth stage not shown in this diagram — the stage in which the hoodoo no longer exists. Due to their ever-eroding tendencies, hoodoos have a relatively short geological lifespan when compared to other rock formations.

"The same processes that create hoodoos are equally aggressive and intent on their destruction," according to the NPS. At Bryce Canyon, "the average rate of erosion is calculated at 2-4 feet (.6-1.3 m) every 100 years."

Scientists estimate that in about 3 million years, Bryce Canyon's erosional patterns will have advanced so far into the present day plateau that it will eventually hit the watershed of the nearby East Fork Sevier River. When this happens, the canyon's hoodoo-forming erosional patterns will be largely replaced by erosional patterns dominated by flowing water.

Bryce Canyon may be one of the most well-known hoodoo-covered landscapes, but these surreal rock formations can be found all around the globe. Continue below for a tour of the world's most outstanding hoodoo destinations, starting with the whimsical terrain of Turkey's Cappadocia region:

Cappadocia — Göreme, Turkey

Fairy chimneys in Cappadocia, Turkey. (Photo: Shchipkova Elena/Shutterstock)

Unlike the sedimentary rocks that make up the hoodoos of Bryce Canyon, the fairy chimneys of Cappadocia are primarily composed of volcanic rock — namely, a thick layer of ashy tuff topped by a layer of basalt. Because tuff is such a soft, porous rock, it erodes quicker than basalt, which is why many of Cappadocia's hoodoos look like giant mushrooms.

Yehliu Cape — New Taipai, Taiwan

The Queen's Head, a solitary hoodoo in Yehliu, Taiwan. (Photo: littcoollll/Shutterstock)

Although there are water-eroded hoodoos all throughout the Yehliu Cape of northern Taiwan, the centerpiece of this special place is generally considered to be the Queen's Head, a natural sandstone "bust" named for its supposed resemblance to Queen Elizabeth I. The hoodoo's thin "neck" is shrinking by 1.5-1.6 centimeters every year, which has many scientists and spectators wondering how long it will be able to support the 1.3-ton "head" that sits atop it.

Bisti/De-Na-Zin Wilderness — New Mexico

Bisti/De-Na-Zin Wilderness in northwestern New Mexico. (Photo: andrmoel/Shutterstock)

The eerie, desolate badlands of the Bisti/De-Na-Zin Wilderness Area in San Juan County is home to some of the most Dali-esque hoodoos on the planet. Many of them even appear to defy gravity. What was once the site of an ancient river delta is now a desert landscape of sandstone, mudstone, shale, coal and silt — the perfect formula for nature to carve some seriously strange rock formations.

Putangirua Pinnacles — North Island, New Zealand

Putangirua Pinnacles in New Zealand's North Island. (Photo: Pi-Lens/Shutterstock)

New Zealand has a reputation for epic, film-worthy landscapes, and the Putangirua Pinnacles is no exception. Situated on the southern tip of North Island, these craggy, heavily eroded pillars of muddy sandstone and siltstone were featured in "The Lord of the Rings" movies.

Goblin Valley State Park — Utah

Sentinel-like hoodoos of Goblin Valley State Park in Utah. (Photo: IrinaK/Shutterstock)

Named for the thousands of oddly expressive, goblin-like rock formations, Goblin Valley State Park is yet another example of the surreal geology in Utah. Many of the hoodoos at Goblin Valley bear striking resemblance to vaguely anthropomorphic figures, like the sentinel-like figures in the photo above.

Earth pyramids of Ritten — South Tyrol, Italy

Earth pyramids of Ritten, Italy. (Photo: haraldmuc/Shutterstock)

These spiky geological formations are composed of moraine clay soil, and they have been slowly eroding for the past 25,000 years. They are currently touted as the tallest group of hoodoos in Europe.

Drumheller Hoodoos — Alberta, Canada

Drumheller Hoodoos in Alberta, Canada. (Photo: Jeremy Klager/Shutterstock)

The mushroom-like Drumheller hoodoos are one of the most distinctive icons of Alberta's expansive badlands environment, which also happens to be one of the world's most prominent fossil-bearing region. As a result, Drumheller boasts a wealth of dinosaur-related tourist activities and destinations, including Dinosaur Provincial Park, Devil's Coulee Dinosaur Heritage Museum, the Royal Tyrrell Museum of Palaeontology and, of course, the "World's Largest Dinosaur."

Demoiselles Coiffées — Pontis, France

Demoiselles Coiffées near Ebrun in the French Alps. (Photo: Hect/Shutterstock)

This exquisite cluster of spindly columns is situated in the French Alps, and remains the most impressive example of hoodoo geology in France. The phrase "demoiselles coiffées" translates to "ladies with hairdos" — a reference to the layers of hard rock (one of which is covered in vegetation) that are perched atop the tip of the tapered column's softer rock.

Kasha-Katuwe Tent Rocks — New Mexico

Hoodoos at Kasha-Katuwe Tent Rocks National Monument near Sante Fe, New Mexico. (Photo: sumikophoto/Shutterstock)

These conical tent rocks are the result of volcanic eruptions that blanketed the land in ashy deposits of tuff and pumice between 6 and 7 million years ago. Today, many of the hoodoos are equipped with boulder caps that perch precariously atop their softer columnar bodies.

According to the U.S. Bureau of Land Management, "some tents have lost their hard, resistant caprocks, and are disintegrating. While fairly uniform in shape, the tent rock formations vary in height from a few feet up to 90 feet."