Yellowstone may be best known for its geysers like Old Faithful, but it's also famous for the supervolcano that lies just beneath the surface.
Now researchers from Arizona State University believe the supervolcano last erupted after two influxes of fresh magma flowing into the reservoir beneath the volcano — and it all occurred much more quickly than previously thought.
Geologists previously believed it would take centuries for a buildup like that to lead to an eruption.
The latest analysis of minerals in Yellowstone reveal the critical changes in temperature and composition built up in decades as opposed to centuries.
Another study from 2013 also showed the magma reservoir that feeds the supervolcano is about two and a half times bigger than previously thought.
A single eruption from this supervolcano would likely darken the sky across the majority of the United States in addition to spewing hot lava from the eruption site.
The Yellowstone supervolcano has erupted three different times, the last of which was 631,000 years ago.
In that eruption, roughly 1,000 cubic kilometers of rock, dust and volcanic ash exploded into the sky and rained across more than half the United States.
Don't go prepping for the end now, however.
The supervolcano in Yellowstone is one of the most monitored volcanoes in the world, and scientists haven't seen any signs of an imminent threat.
The U.S. Geological Survey puts yearly odds of another Yellowstone eruption at 1 in 730,000. If that slim chance does occur, now we know we'll at least have decades to prepare as opposed to centuries.