Does South Dakota Have Volcanoes? Exploring the State’s Volcanic Features

Except for the explosion of the Yellowstone super-volcano, which is always possible, here in South Dakota, we don't worry much about volcanos. Which is good because we're already worrying about tornados, blizzards, huge thunderstorms, drought, floods, frigid cold, and extreme heat. And bugs.

Well, I should say we MOSTLY don't have to worry about volcanos in South Dakota.

MORE: What If a Nuclear Bomb Fell on South Dakota’s Largest Cities? Here’s the Science

Volcanos in the United States

It's been 45 years since a volcano erupted in the contiguous United States. On May 18, 1980, Mount St. Helens in Washington State exploded, sending ash, rocks, mud, and a pyroclastic flow across the landscape.

Nearly 60 people died in the eruption that day, and hundreds of miles of wilderness around the mountain were destroyed.

Volcanoes in South Dakota? Kind Of—Keep Scrolling for the Story

The Mount St. Helens eruption was just one of two recorded volcano eruptions in the lower 48. The other was in 1915 when Lassen Peak in northern California erupted.

Alaska had a handful of large eruptions over the years, as recently as 2008. And, of course, Hawaiʻi has its famous volcanos, like the Kīlauea Volcano.

Volcanoes in South Dakota? Kind Of—Here’s the Story

The eruptions of volcanos in Hawaiʻi are always fascinating events to follow.

Fascinating to me anyway, sitting here thousands of miles away and safely watching from my computer. I'm sure it's a very different experience for the people living on the island.

MORE: What Happens to South Dakota if the Yellowstone Super Volcano Erupts?

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Are There Volcanoes in South Dakota?

The anniversary of the eruption of Mount St. Helens got me thinking. Do we have any volcanoes, or possible volcanoes, in South Dakota?

East River South Dakota doesn't really have any obvious signs of volcanic activity. It's mostly farmland scraped flat by ancient glaciers.

The hills and valleys here were formed mostly by wind and water erosion and the retreating glaciers at the end of the last Ice Age.

West River South Dakota, however, has the Black Hills.

Volcanoes in the Black Hills of South Dakota

The closest thing to a volcano in the 605 are geologic features in the Black Hills called laccoliths.

Some fifty million years ago, magma (molten rock; it's called lava when it comes out of the ground) pushed up the crust of the Earth in the area. Like your foot pushing up the bed sheets, the magma pushed up until it formed hills called laccoliths.

If the magma had punched through the bubble it was making (ripped through the bed sheets), it would have erupted into a full-fledged volcano.

South Dakota's Hidden Volcanic Past

Bear Butte in Bear Butte State Park near Sturgis, South Dakota, is a great example of a laccolith in the Black Hills.

It's not actually a butte, meaning an area rising from the surrounding land caused by erosion. A butte is made when the land is worn away, leaving a kind of big hill. Here, magma did it, then erosion took over.

Bear Butte may have actually erupted when it was formed or sometime in the distant past, but the erosion likely destroyed the evidence.

The mountain, alone in the sea of grassland, has long been a sacred site for many Native Americans. It is also known as Mato Paha or Bear Mountain to the Lakota and Noahvose to the Cheyenne people.

Unveiling South Dakota's 'Volcanoes': Laccoliths

Elkhorn Peak, Crow Peak, Crook Mountain, and Citadel Rock were also formed by magma pushing the ground up. Devil's Tower, also known as Bear Lodge Butte, in Wyoming, is a feature called a 'volcanic neck.'

An interesting bit of trivia: the gold in the Black Hills was likely created around the same time as these volcanic mounds.

READ MORE: Debunking 5 Common Tornado Myths in South Dakota

These giant hills are probably the closest thing we have to a volcano in South Dakota. And if we're all lucky, we'll never know any different.

Running from lava flows and ash doesn't sound like a lot of fun. Then there are the lava bombs to deal with, oh, and the always fun pyroclastic flow.

What is a volcano?

A volcano is a mountain or hill with an opening at the top where melted rock, called magma, can come out. When magma reaches the surface, it's called lava. Volcanoes can also let out gas and ash into the air.

How do volcanoes happen?

Volcanoes happen when magma from deep inside the Earth pushes its way to the surface. This can happen because the Earth's crust has cracks or because the magma builds up so much pressure that it forces its way out.

What are the most active volcanoes in North America?

Some of the most active volcanoes in North America are:

• Kīlauea in Hawaii: This volcano erupts often and has been active for many years.
• Mount St. Helens in Washington: It had a big eruption in 1980 and still shows activity sometimes.
• Mount Redoubt in Alaska: This volcano has erupted many times, most recently in 2009.

Sources: South Dakota Magazine, South Dakota GFP, Encyclopedia of the Great Plains, Wikipedia

ABOUT THE AUTHOR: Ben Kuhns is just some guy on the internet. He is a wannabe writer, and his wife thinks he's funny. He writes for Results-Townsquare Media in Sioux Falls South Dakota.