I like mud pots and so do children as they make a great plop plop noise as the sulphur gas escapes from the depths of the earth. They may not be as colourful as the hot springs and pools but they are one of the geothermal volcanic features that makes Yellowstone National Park so unique.

Mud Caldrons are slightly different as the boiling action you see is caused by carbon dioxide and other gases rising from below and passing though the water in the pool. Mud Geyser occur if the underground steam vents are of small girth. Pressure builds up the mud explodes upwards in a column of muddy water, 7-10 ft in diameter, up to 50 ft in the air and can cover trees.

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