William Pyroclastic flow (火砕流-かさいりゅう) is something you don’t want to notice, because if you notice it, you’ll likely be soon dead. Think about the charcoal from your barbecue spreading over a few hundred kilometers. I’m not saying it’s gonna happen soon, but I’m not saying that it’s not, either. But when it does, there’s really nothing you can do. Just ask the people from Pompei.