Evidence of an eruption 5,000 times larger than Mount St. Helens was found in the Utah desert, with traces of ash identified as far away as Nebraska. These supervolcanoes aren’t active today, but 30 million years ago more than 5,500 cubic kilometers of magma erupted during a one-week period near a place called Wah Wah Springs. By comparison, this eruption was about 5,000 times larger than the 1980 Mount St. Helens eruption.