Wonders like the Old Faithful geyser and the Grand Prismatic Spring are products of the geothermal activity still seething below the park, which is driven in turn by the vast magma plume that feeds the supervolcano. It has the ability to expel more than 1,000 cubic kilometers of rock and ash at once — 2,500 times more material than erupted from Mount St. Helens in 1980, which killed 57 people. "This helps explain the distribution from large Yellowstone eruptions of the past, where considerable amounts of ash reached the west coast," he added. “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,” study co-author Hannah Shamloo told the New York Times. The early evidence, presented at a recent volcanology conference, shows that Yellowstone’s most recent supereruption was sparked when new magma moved into the system only decades before the eruption. That could blanket most of the United States in a thick layer of ash and even plunge the Earth into a volcanic winter.
– Should it ever erupt, a supervolcano beneath Yellowstone National Park could blanket North America in an ash cloud, wipe out communications, and alter the climate. Given that eruptions of supervolcanoes buried on our planet—and there are several—are thought to occur every 100,000 years or so, however, the likelihood of such an event during your lifetime is small, reports the New York Times. As comforting as that may be, new research out of Arizona State University is far less so. Whereas researchers previously thought such an eruption would be centuries or millennia in the making, an analysis of fossilized ash left over from Yellowstone's last supereruption 630,000 years ago reveals the process could take only decades. Tiny crystals left over from underground magma at Yellowstone show the first sign of the last supereruption was a spike in temperature that coincided with the movement of new magma into the reservoir beneath the supervolcano. The crystals also reveal a supereruption followed much quicker than scientists previously thought—perhaps within decades, or what Popular Mechanics calls "a geologic snap of the finger." This is the first indication that "the conditions that lead to supereruptions might emerge within a human lifetime," which one researcher describes as "shocking," per the Times. For now, though, you can rest easy. The lead scientist at the Yellowstone Volcano Observatory tells National Geographic there's no sign of any "magmatic event" at this time. (You might outrun a supervolcano's lava anyway.)