They’re born. They live once, erupting for a period that might last for days, years or decades. Then, they go dark and die. This narrative describes the life of a monogenetic volcano, a type of volcanic hazard that can pose important dangers despite an ephemeral existence. The landscape of the southwestern U.S. is heavily scarred by past eruptions of such volcanoes, and a new study marks a step toward understanding future risks for the region.