Back Basin Mudpots (Norris)

The mudpots are located in the Back Basin section of the Norris Geyser Basin in Yellowstone National Park, Wyoming. Norris is famously known as the hottest and most acidic thermal area within the entire park.

The Back Basin is home to Steamboat Geyser, which holds the record as the world's tallest currently active geyser. Visitors often walk the boardwalks through this area hoping to witness one of its unpredictable, massive water eruptions.

Mudpots form when microorganisms convert hydrogen sulfide gas into sulfuric acid, which breaks down the surrounding rock into wet clay. Because the thermal feature is highly acidic, it boils up as thick, bubbling mud rather than shooting clear water like a traditional geyser.

The Back Basin features several thermal features that have shifted from active geysers to quiet hot springs or mudpots over the decades due to shifting underground energy. Examples include Echinus Geyser, which used to erupt frequently but has become largely dormant in recent years.