Opal Pool
Opal Pool in the Midway geyser basin is one of many geothermal hot springs in the Yellowstone National Park Caldera. Water heated beneath the ground to near boiling surfaces in these springs under low pressure, creating a clear pool. In other areas it arises as geysers or mudpots. The bright colors around the springs are from bacterial action. Opal Pool actually does erupt occasionally as a geyser, but is unpredictable.
Opal Pool
Opal Pool in the Midway geyser basin is one of many geothermal hot springs in the Yellowstone National Park Caldera. Water heated beneath the ground to near boiling surfaces in these springs under low pressure, creating a clear pool. In other areas it arises as geysers or mudpots. The bright colors around the springs are from bacterial action. Opal Pool actually does erupt occasionally as a geyser, but is unpredictable.