Overview

• Geologists found the previously undocumented light-blue pool during routine USGS maintenance in April 2025 in the Porcelain Basin west of Tree Island.
• The feature spans about 13 feet across, holds water at approximately 109 °F, and sits roughly one foot below its rim.
• High-resolution satellite imagery shows no sign of the pool before December 19, 2024, a small depression by January 6 and a fully formed water body by February 13 2025.
• Infrasound sensors detected weak acoustic signals on December 25, 2024, January 15 and February 11 without seismic tremors, indicating multiple small steam-driven explosions.
• Ongoing monitoring by USGS and the Yellowstone Volcano Observatory confirms the pool is stable with no indications of imminent hazards, underscoring Yellowstone’s dynamic geothermal nature.