• A bull elk bugles in Yellowstone National Park

    Yellowstone

    National Park ID,MT,WY

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  • Craig Pass Closed for the Season; Mammoth to Norris, Expect 30-minute Delays

    The road linking West Thumb and Old Faithful is closed for the season—traffic should detour through West Thumb, Lake, and Canyon. More »

Mudpots and How They Work

A bubbling mudpot

Bubbling Mudpot

Mudpots are acidic features with a limited water supply. Some microorganisms use hydrogen sulfide, which rises from deep within the earth, as an energy source. They help convert the gas to sulfuric acid, which breaks down rock into clay. Various gases escape through the wet clay mud, causing it to bubble. Mudpot consistency and activity vary with the seasons and precipitation. The sights, sounds, and smells of areas like Artist and Fountain paint pots and Mud Volcano make these curious features some of the most memorable in the park.
 
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Did You Know?

Fishing Bridge.

You cannot fish from Fishing Bridge. Until 1973 this was a very popular fishing location since the bridge crossed the Yellowstone River above a cutthroat trout spawning area. It is now a popular place to observe fish.