Think You Can Drive Fast Enough to Escape an Erupting Volcano?

A massive pyroclastic flow from a 2014 eruption of Sinabung in Indonesia. James Reynolds, used by permission. Imagine being near a volcano when it unleashes a gigantic eruption. I'm not talking something fairly piddling like the 1980 eruption of Mount St. Helens or even the 1991 eruption of Pinatubo in the Philippines. I'm talking one of these eruptions that the tabloids and conspiracy websites say will destroy civilization, like Yellowstone or Toba. The common response is that everyone within hundreds of kilometers of the volcano would be killed almost instantly thanks to the fast moving pyroclastic flows that can rush outward from the caldera volcano for more than 150 kilometers (~100 miles). That idea is based on what we can see from these flows at smaller eruptions, where they race down the sides of the volcano at speeds over 500 kilometers per hour (300 mph). Cities like Pompeii and St. ...