Steamboat Geyser eruption from boardwalks in Norris Geyser Basin, 2001

Heat and volcanic gases from slowly cooling magma rise and warm the dense salty water that occupies fractured rocks above the Yellowstone magma chamber. That brine, in turn, transfers its heat to overlying fresh groundwater, which is recharged by rainfall and snowmelt from the surface. Water boiling at depth below the surface is hotter than the temperature of boiling at the surface. If it rises quickly, this superheated water can flash to steam, propelling both steam and hot water to the surface as a geyser. More commonly, hot water rises and loses its heat at a steady rate, flowing to the surface as a hot spring.

Steamboat, located in Norris Geyser Basin, is one of Yellowstone's most famous geysers. Eruptions occur sporadically, but are well worth the wait. Columns of hot water reach heights up to 100 meters. This is followed by a raucus steam phase that can last for over a day, loudly discharging steam nearly 200 meters into the atmosphere.