The U.S. Volcano That Could End Us All... And It's Hiding In Plain Sight!

AJ McMullen
Dec 10, 2025
2 min read

It all started with a simple, slightly paranoid thought: Are there any active volcanoes in the United States?

Turns out, not only are there 170 of them, but the most massive, most active one is right beneath our noses, drawing millions of tourists every year.

I’m talking about Yellowstone National Park.

Your mouth might drop open, just like mine did, when you realize those mesmerizing, bubbling geysers are the visible features of one of the world’s largest Supervolcanoes. We visit, take beautiful photos of Old Faithful, and leave, completely unaware of the terrifying, enormous reality happening beneath the surface.

The Caldera Conundrum

The surface of Yellowstone is beautiful, but the truth underneath is mind-boggling. The underground magma channels of the Yellowstone Caldera span an area of roughly 10,000 square miles. That incredible size makes it the largest active volcano in the entire United States.

Why are volcanologists from around the globe so interested in this particular park? Because, scientifically speaking, this sleeping giant is arguably overdue.

The last major eruption was an estimated 640,000 years ago. While many small eruptions happen globally every day that we never hear about, the activity in Yellowstone is different. When teams of global scientists convene to monitor the geysers, you have to wonder: What are they really worried about?

The Inevitable Day

This isn’t a hypothesis; it's the science of geology. For Yellowstone, it’s not a matter of if it will erupt, but when.

When that day arrives, Yellowstone National Park will be lost under miles of magma. The immediate kill zone is projected to cover the majority of Wyoming, Montana, Utah, and Idaho in dangerous ash and fire. But the fallout doesn't stop there. The rest of the country will face a dark, ash-choked sky for months, triggering an environmental and societal catastrophe. On top of the volcanic destruction, the sheer crustal stretching will guarantee devastating earthquakes.

When will we need to hide from a sky covered in ash? Only our planet knows.

Find Out What Happens When the Earth Breaks...

The sheer, terrifying scale of a Yellowstone-level event was the inspiration for my new novel, Legacy of the Arcanin Flame.

Set close to the Caldera in Idaho Falls, Idaho, the story imagines the beginning of this cataclysm.

Tawnie Simms discovers her son, Milo, is cursed with a sacred power that makes him the catalyst to the apocalypse. As she tries to keep him safe from an army of unknown soldiers who want to kidnap him, Tawnie must decipher a million-year-old text from an ancient civilization who predicted the end of humanity, and figures out how to change the fate of the world.

Tawnie must figure out how to change the fate of humanity while trying to keep them safe from the army of unknown soldiers trying to kidnap him.