Crested Pool

NPS / Neal Herbert

Quick Facts

Location:

Old Faithful

Amenities

1 listed

Historical/Interpretive Information/Exhibits

With temperatures that average temperate of 191.1°F (88.4°C), Crested Pool is almost constantly boiling, sometimes to 6 feet (2 m) or more.

The extreme heat prevents most bacterial growth, resulting in exceptionally clear blue water. Boiling is particularly active along the intricate sinter formation circling the spring, the “crested” edge. Listen for the sizzling.

Crested Pool has an average pH of 8.9 and an average conductivity of 2269 uS/cm.

Hot Springs

Hot springs are the most common hydrothermal features in Yellowstone. Their plumbing has no constrictions.

Superheated water cools as it reaches the surface, sinks, and is replaced by hotter water from below.

This circulation prevents water from reaching the temperature needed to set off an eruption.

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.