While evidence for high water levels exist, Black Pearl Geyser appears to be a cavernous opening in the ground surface that is continuously steaming. Water inside the depression constantly boils. Moss-like vegetation surrounds the opening at the surface. Black Pearl Geyser goes through years of dormancy, but had a period of activity in the years following the 1959 earthquake, ending in 1967.

Black Pearl Geyser has an average temperate of 192.7°F (89.3°C), an average pH of 8, and an average conductivity of 1950 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.

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.