The fear of a Yellowstone supereruption, which ultimately went viral, may have begun back in February when a seismometer called B944 began sending senseless data to a public viewer at the University of Utah's seismographic station, as George Black reports in The New Yorker.

Luckily for most of the U.S., the likelihood this eruption would happen is pretty low: about one in 100,000 any given year. If it did happen, it would be pretty devastating, though.

The danger of these eruptions isn't just lava in the area around the volcano — the ash alone poses a serious threat. Breathing hot ash can result in respiratory burns, and the minerals it contains can irritate the skin and cause abrasions in the eyes and the respiratory system. The pileup of ash on rooftops has resulted in building collapses, and ash accumulation on streets can make roads dangerous, if not impossible, to navigate. And ash in the sky disrupts air travel by blocking visibility and interfering with electronics.