Churn Geyser is a large, clear pool with some geyserite deposits lining the edges and in the outwash channel of the pool. A deep vent sits in the center of the pool and the rest of the pool is shallow with orange thermophiles lining the edge and continuing into the outwash channel. Recently, Churn Geyser's activity seems to be related to activity cycles of Sawmill Geyser and other geysers in the Sawmill complex, with eruption intervals in the 5–20 minute range.

Churn Geyser has an average temperate of 168.9°F (76°C), an average pH of 7.4, and an average conductivity of 2102 uS/cm.

Geysers

Geysers have constrictions in their plumbing systems that prevent water from moving freely to the surface where heat would escape. Water beneath the constrictions creates a buildup of steam. Eventually the steam pushes water past the constrictions and the geyser erupts.

Upper Geyser Basin

The majority of world’s active geysers are in the Upper Geyser Basin, including Old Faithful. Only four other places in the world have large concentrations of hydrothermal features: Russia (Kamchatka), Chile, New Zealand, and Iceland.

The heat for the hydrothermal features comes from Yellowstone’s volcano. Molten rock or magma may be as close as 3-8 miles (5-13 km) underground. Rain and snow supply water that seeps down several thousand feet (more than a kilometer) below the surface where it is heated.

Underground cracks form a natural plumbing system. Hot water rises through the plumbing to produce hot springs and geysers.

Use Caution in Hydrothermal Areas

• Stay on boardwalks and designated trails.
• Hydrothermal water can severely burn you.
• Never run, push, or shove.
• Supervise children at all times.
• Do not scratch hydrothermal mats.

You are responsible for your safety.

Think safety, act safely. Yellowstone is a dangerous place.