Eruptions of Sawmill Geyser
are spectacular though also quite variable, lasting from several minutes to 3 or 4 hours, separated by quiet periods of 1 to 3 hours. This activity is evident from the large, well established sinter formations around the vent, measuring 40 feet across. The geyser's name (bestowed in 1871) refers to the fierce grinding sound made during an eruption. When inactive the vent contains gently boiling, light blue water in a nearly pure white crater; the water level is low, not visible, just after an eruption, and gradually rises leading up to the next performance.
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