Black Pool


Not long ago, Black Pool really was black. Lower water temperature allowed thick mats of dark green and brown thermophiles to grow in the pool, causing it to appear black. The water temperature rose during the summer of 1991, killing these organisms. Black Pool also erupted that summer and several times the following winter. Like Abyss, Black Pool is now one of Yellowstone's most beautiful pools.

*Adapted from the NPS West Thumb Geyser Bain Trail Guide and the West Thumb Interactive Tour

Feature Type

Not Reported

Inventory ID



Latitude: 44.41822
Longitude: -110.5718
Survey Date: June 22, 2000

Geographic Area: West Thumb
Thermal Region: West Thumb Geyser Basin
Thermal Complex: Lower Group
Ranger District Contact: Grant District, Matt Vandzura (307) 344-2601

Feature Data

Data Source Supplied By Sample Date Temp Vent Temp pH Cond Extended Data
Park 6/22/2000 72.9°C 74°C 7.97 1000 µS/cm No
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