Black Diamond Pool is a large murky blue pool with water flowing into other pools nearby. Soft sinter and sparse vegetation surrounds the area of the pool. Outflow from the pool forms braided channels of orange and green thermophiles. These large pools formed from hydrothermal explosions. While not all historic explosions are known, Black Diamond Pool erupted black murky water after an earthquake in July 2006, with several explosive eruptions in the following days. Eruptions continue to be infrequent since, with the last eruption observed in 2016.

Black Diamond Pool has an average temperate of 148.5°F (64.7°C), an average pH of 8.2, and an average conductivity of 2092 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.

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.