Geyser eruptions, like volcanic eruptions, are a mystery, so the reactivation of Steamboat Geyser in Yellowstone in 2018 provided an opportunity to explore why geysers turn off and on, and what determines their periodicity. Researchers found little evidence of magma moving below the geyser, meaning no sign of imminent hydrothermal eruptions, but did discover a relationship between the height of the column and the depth of the water reservoir.