The reason that Fuego is far more deadly than Kilauea is that they are really two different kinds of volcanoes. The Hawaiian volcano is what’s called a shield volcano, where the lava sort of oozes out of the ground rather slowly and not particularly dangerously. By contrast, Fuego is a stratovolcano with much thicker lava. Gases build up inside the lava until the volcano erupts explosively. It can eject lava and rocks and ash all over the place. And it creates what’s called a pyroclastic flow. It forms a big, very toxic, very dangerous cloud that’s actually denser than air so it can sort of flow down a mountainside very quickly — up to several hundred miles an hour — and quickly envelop people who can’t get out of the way. One of the problems in Guatemala is that a lot of people are living close to the volcano and were trapped when it erupted. By contrast, in Hawaii the lava moves so slowly that people have the chance to get out of harm’s way. So in Hawaii, the damage is mainly to buildings, not people.