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  Sawmill Geyser
Feature Type: Geyser
Geyser/Spring Type: Fountain geyser

Upper Geyser Basin
Grand and Castle Group

Sawmill is the largest member of the Sawmill Complex. It is a fountain-type geyser, its bursting eruptions playing through a funnel shaped pool. Typical intervals are one to three hours. Durations can range from 9 minutes to more than 4 hours with most in the 30 to 50 minute range. Heights can exceed 35 feet. When the complex is in the Sawmill Mode, Sawmill Geyser is usually in eruption about one third of the time.

Sawmill was named for the whirring noise it makes during its eruption and/or for the rotary motion in its pool during the eruption. Either way, Sawmill is an enjoyable geyser. It is fun to watch and to hear.

What to look for:
After an eruption, Sawmill drains, leading many first-time visitors who see the empty crater, to believe that the geyser is dead.

Prior to an eruption, Sawmill, along with the other features in the complex,begin to slowly fill. At this time, Tardy and Spasmodic often start to erupt. preceding Sawmill. As the water rises, a battle often takes place between Penta and Sawmill. Whichever erupts first dooms the other, causing the other to drain without erupting.

Just prior to the eruption, Sawmill will be near or just at overflow. At this time, bubbles start rising in the pool. At first the bubble collapse before they reach the surface but eventually they reach the surface, at which point the eruption is usually near.

After an eruption of Sawmill drains and all of the other features in the complex drop from a few inches to many feet. In general, the longer the eruption the deeper the drain. A long eruption of Sawmill causes a "deep drain" which often accompanies rare behavior in some of the other members of the complex.

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Sawmill Geyser taken by Jared Moulding. Note Old Faithful Geyser erupting in the background.

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Please note - this site is currently under constuction. Please visit for more information.  Last update 01-29-2017

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