Twin Geysers


Twin Geysers—one geyser with two vents—has short periods of dramatic eruptions and extended periods of dormancy. After a 23-year dormancy, it began erupting again in 1998; its last known eruption was in 1999. Visitors lucky enough to witness an eruption see a two-part event. The west vent erupts 70 feet (21 meters), then the east vent erupts more than 100 feet (30 meters).

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

Feature Type


Inventory ID



Latitude: 44.41726
Longitude: -110.5727
Survey Date: June 21, 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 6/21/2000 76.9°C 94°C 8.1 2000 µS/cm No
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