A hydrothermal explosion in Yellowstone National Park, where superheated underground water rapidly flashes into steam, violently ejecting boiling water, mud, rocks, and debris—recent examples include the 2024 Biscuit Basin event and others captured on video.

Colloquial reference to the feared supervolcanic eruption of the Yellowstone Caldera, a dormant supervolcano in Wyoming, USA; despite internet hype, scientists emphasize it's not imminent, with the last major eruption 640,000 years ago.