Rudyard Kipling, who visited Yellowstone in 1889, immortalized this basin by referring to it as "Hell's Half Acre." You can see why - the ground is spewing steam in many spots.


What looks like smoke is actually steam from hissing and roaring fumaroles. Gases such as steam, carbon dioxide, and a little hydrogen sulfide, rush from the earth through the vent. Its channel system reaches down into the hot rock masses, but it contains very little water. When water contacts the hot rock, it changes into steam.