Book 12, Question 82
Why Do Fumaroles Hiss?
A fumarole is a vent in the ground that lets out steam and gases, and it hisses like a kettle or a bike tire! Fumaroles can keep working for years after an eruption has ended. The steam and gases can be hot and harmful, so stay far away and follow grown-ups and park signs.
More fun facts
- Fumaroles are openings in the ground that give off steam and volcanic gases.
- Their hiss and roar comes from gases rushing out through the vent.
- The gases are mostly steam, with carbon dioxide and a little hydrogen sulfide.
- Fumaroles are the hottest hydrothermal features in Yellowstone.
- Hydrogen sulfide from fumaroles can turn into sulfuric acid and yellow sulfur.
- A Yellowstone vent called Hurricane Vent was once a steamy, noisy fumarole.
Sources: National Park Service, National Park Service, U.S. Geological Survey, U.S. Geological Survey
Questions kids ask
Is a fumarole a kind of geyser?
No. A fumarole lets out steam and gas, not shooting water.