Rebecca L. Latson/Getty Images
Since 1872, Yellowstone National Park has been a protected natural wonder that draws millions of visitors each year. Beneath its iconic geysers and waterfalls lies an equally spectacular—and terrifying—secret: an active supervolcano that ranks among the world’s largest volcanic systems.
Yellowstone sits atop a mantle hotspot, where rising plumes of hot, molten rock feed volcanic activity in the crust far from any plate boundary. Over the past 2.5 million years, this hotspot has produced three colossal caldera‑forming eruptions: the Huckleberry Ridge event 2.1 million years ago, the Mesa Falls event 1.3 million years ago, and the Lava Creek event 631 000 years ago. These cataclysmic blasts, along with subsequent lava flows, erosion, and faulting, sculpted the modern Yellowstone Plateau.
To grasp the scale of these eruptions, compare them with the 1980 Mount St. Helens event, which ejected 2.5 km³ of material (roughly 1 million Olympic swimming pools) over 600 km². In contrast, the Huckleberry Ridge eruption expelled about 2 450 km³—6,000 times more—across an area of 15 500 km².
Photography By Deb Snelson/Getty Images
Recognizing the park’s supervolcanic nature, the U.S. Geological Survey (USGS) monitors Yellowstone 24/7. Mark Stelten, a research geologist and deputy Scientist‑in‑Charge of the Yellowstone Volcano Observatory (YVO), explains that the annual probability of a volcanic eruption is roughly 0.001 %. While the next eruption could still be thousands or even tens of thousands of years away, the YVO’s sophisticated forecasting models and real‑time data give scientists early warning if activity starts to ramp up.
“Volcanoes typically provide weeks to months of warning before an eruption,” says former YVO Scientist‑in‑Charge Jake Lowenstern. “Yellowstone’s large‑scale system may take longer to show clear precursors, but a significant eruption would have global climatic implications due to the vast volume of ash and gases released.”
For now, the most common hazards in the park are hydrothermal explosions and lava flows. Hydrothermal events, such as the Biscuit Basin eruption in July 2024, are generally small and occur every few years. Lava flows, while frequent, are usually confined to the park’s interior and pose limited risk outside the immediate area.
