Researchers are saying the supervolcano sitting beneath Yellowstone National Park could erupt sooner than thought -- and could possibly plunge the planet into a "volcanic winter."
It's been roughly 631,000 years since Yellowstone's last super-eruption and, until now, scientists thought it would take centuries for the supervolcano to make the transition, according to National Geographic.
Now, after analyzing minerals in fossilized ash from Yellowstone, researchers from Arizona State University are saying the lava-filled mountain could erupt in just a few decades.
RELATED: Click through photos of the Yellowstone supervolcano
The discovery arrives several years after a 2011 study found that the ground above Yellowstone's caldera had risen as much as 10 inches in some places over the course of seven years.
"It's an extraordinary uplift, because it covers such a large area and the rates are so high," the Bob Smith, an expert in Yellowstone volcanism at the University of Utah, told National Geographic at the time.
Researchers are also saying the supervolcano has the ability to produce an eruption of a thousand times more powerful than Mount St. Helen's eruption in 1980 and eject more than 1,000 cubic kilometers of rock and ash -- which could blanket large areas of the US.
Arizona State graduate state Hannah Shamloo, who developed the theory that there was a much shorter timeline than once anticipated for an eruption, spent weeks with several colleagues at the site in Yellowstone where they collected and studied fossilized ash from its last eruption.
"It’s shocking how little time is required to take a volcanic system from being quiet and sitting there to the edge of an eruption," Shamloo told New York Times, while adding that more research is necessary before drawing definite conclusions.
Though the pair presented the study at a recent volcanology conference before the American Geophysical Union in 2016, it has yet to be peer-reviewed.
RELATED: Amazing lava fountains captured at night
- This article was initially published on AOL.com: Yellowstone supervolcano may be only decades from a catastrophic eruption