Fumaroles also known as steam vents, can be found throughout Yellowstone and are the hottest of the hot reaching temperatures of 280°F (138°C). A fumarole exists when a hydrothermal feature has so little water in its system that the water boils away before reaching the surface. Fumaroles emit large amounts of gases, primarily steam and carbon dioxide. When the gases emerging from a fumarole contain high amounts of sulfur the fumarole is known as a solfatara. Often the gases hiss and whistle as t