Yellowstone ‘Super Eruption’ Could Blanket U.S. in Ash, Study Finds

If Yellowstone erupted into a massive, ash-spewing volcano, how far might the plume travel across the continental United States? From coast to coast, blanketing every city in ash, according to an unsettling new study.

Geophysicists developed a computer model of a Yellowstone “super eruption” that would spew 330 cubic kilometers of volcanic ash into the sky. The resulting ash cloud, depending on wind conditions, would blanket the continental United States in ash deposits of varying thickness, according to the study, published late August in the journal Geochemistry, Geophysics, Geosystems.

New York and Washington D.C., would get a light dusting of ash measuring roughly one-tenth of an inch, while San Francisco and Seattle would get a heaping 2 inches. Billings, Montana, meanwhile, would have to dig out from a 70-inch pile up.

If the findings sound far-flung, so to speak, researchers point out that Yellowstone’s last massive eruption spewed ash over tens of thousands of square kilometers. Deposits from that eruption have been traced as far afield as Canada and the Gulf of Mexico. Fortunately, the last time Yellowstone erupted on that scale was some 2 million years ago and counting.