Guatemala's Fuego volcano eruption killed 25 people on Sunday. Hawaii's recent Kilauea eruption hasn't killed anyone yet, but it continues to wreak havoc a month later. Kilauea's primary mode of destruction is lava, but Fuego has unleashed pyroclastic flow. Pyroclastic flow is a nasty mix of ash, rock and volcanic gases that can be much more dangerous than lava. In Guatemala, pyroclastic flow from Sunday's eruption topped 1,800 degrees Fahrenheit, CNN reports.