What Is A Slot Canyon?

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It is exhilarating to explore the earth’s natural heritage. From deep underwater trenches to soaring mountain peaks, there are a vast array of places to investigate and marvel at. Mountains seem so solid and forbidding. It is mindblowing to imagine that water and wind can cut the seemingly impenetrable mountain surfaces to create canyons. There are different kinds of canyons, and one of them is known as a slot canyon.

A slot canyon is a deep, narrow gorge with a height considerably greater than the width. In most slot canyons, the height is ten to one hundred times the width. Slot canyons primarily occur in areas of sandstone or limestone. However, there are instances where they occur in basalt or granite rock.  

When we think of a slot, we generally think of a coin slot on a parking meter or something similar. A very narrow opening that is quite deep. This aptly describes slot canyons.

What Are The Features Of A Slot Canyon?

Slot canyons are characterized by their long, narrow dimensions. The depth is much greater than the width. The height is usually more than ten times the width and sometimes more than one hundred times the width. You might have a canyon only one to two feet wide but more than one hundred feet high.

The sides of a slot canyon are steep. They may be smooth or jagged depending on the rock deposits in the area. There are often only one or two entrance or exit points in slot canyons, making it difficult to get out of them in a hurry.  

Slot canyons may have streams that run along the bottom, and waterfalls are typical features. Slot canyons in arid regions will only have water present during the rainy season. Depending on the precipitation patterns and rates, they may even be dry for many years.

Debris such as soil, fallen rock, tree trunks, and large branches may be found in a slot canyon. Evidence of the debris can be seen at the base of the cliffs. If the slot canyon is narrow, large debris may get stuck between the two sides of the canyon.  

The ecology in slot canyons may be vastly different from the environment, fauna, and flora on the upper plateau. The cliffs bracketing on either side of the canyon influence the humidity, wind, and sun exposure.

How Do Slot Canyons Form?

Slot canyons originate from cracks in the ground that formed from the shifting of tectonic plates. Water enters the cracks and erodes the lower surface, making the crack deeper.

Material loosened by the water is carried along by the flow and increases the erosion as it scrapes and tumbles on the ground surface. Flooding causes increased water volume, deepening the crack rapidly during rainy seasons.

Slot canyons may also form from rivers following the land’s natural contours. Over time the riverbed is eroded and deepened, resulting in a deep narrow valley.

As the valley deepens, winds begin howling through, eroding rock and sand off the surfaces.

Slot canyons most commonly occur in areas with soft rock such as sandstone or limestone. They are sometimes seen with harder rock types such as basalt and granite.

A common feature of the slot canyons is the clearly visible rock strata in the canyon walls. The strata have varying mineral deposits, which result in different colored layers, making the canyon extremely beautiful.  

Hard rock strata encased in soft rock may give rise to shelves or jagged features in the wall as they erode more slowly. Although outcroppings in the canyon walls may occur, the surfaces are smooth due to the action of the water.  

Are Slot Canyons Dangerous?

Slot canyons are renowned for being perilous for explorers and visitors. There are a few reasons for the danger.

  • Slot canyons are prone to flash floods. Rainwater collects in the steep, narrow valleys and moves at tremendous speeds with excessive force. The density of the water makes it an impossible force to withstand.
  • Slot canyons can have a quick rise in water level, moving from a small stream to a deep rushing river in a few minutes. The rain may have fallen several miles upstream, and visitors to the area can be unaware of the danger as they did not witness any rainfall.
  • Slot canyons have very few exit points. The sides are steep and washed smooth by water, making it impossible to climb the cliffs. If floodwaters catch someone in a slot canyon, it is challenging and sometimes impossible to get out.
  • Slot canyons have loose rocks, tree trunks, and large branches which may get jammed between the opposite cliffs. The boulders and trees may slip due to erosion and come crashing down on unsuspecting explorers.

Aron Ralston was hiking and exploring Bluejohn Canyon in April 2003. Bluejohn is a slot canyon in Wayne County in Utah, known for its many slot canyons. During his hike, a dislodged boulder fell, trapping his right wrist between the immense rock and the canyon side.

After five days, he deliberately broke his radius and ulna. He amputated a portion of his arm with a multi-tool. To get out of Bluejohn slot canyon, he had to hike through the remainder of the canyon and rappel down a sixty-five-foot cliff. After exiting the canyon, he still had to walk a further seven miles to get help.

Aron Ralston’s story highlights the dangers of falling debris in slot canyons.  

What Are Some Famous Slot Canyons in the USA?

Slot canyons occur worldwide, but certain regions have them in abundance. The southwestern USA has a combination of soft rock and extreme climate, which has resulted in the formation of many slot canyons.

Antelope Canyon in Arizona is formed in Navajo sandstone. The canyon is divided into two sections, the upper and lower Antelope Canyons. It is known for its spectacular colors, which are caused by the presence of quartz, hematite, goethite, and limonite in the sandstone.

Utah has the famous Robber’s Roost Canyon and Buckskin Gulch, the longest and most dangerous slot canyon in the USA. Buckskin Gulch covers twelve miles is ten feet wide with canyon walls four hundred feet tall.

The Grand Canyon includes five slot canyons that form side branches of the main canyon.


Slot canyons are remarkable geographical features that capture the imagination and beckon avid adventurers. They are beautiful but dangerous features to explore. Care should be taken when planning a hike through any slot canyon. Ensure that friends or family always know where you are hiking.