Overview

• Yellowstone Volcano Observatory geologists discovered the pool on April 10, 2025, while servicing temperature logging equipment in the Porcelain Basin.
• The feature measures about 13 feet across, holds water at roughly 109 °F, and sits one foot below its light-blue surface rim.
• High-resolution satellite imagery shows no sign of the pool before December 19, 2024, a cavity by January 6, 2025, and a fully formed pool by February 13, 2025.
• Infrasound sensors detected weak acoustic signals on December 25, 2024, January 15 and February 11, 2025, without corresponding seismic activity, supporting a series of minor hydrothermal explosions.
• Continuous monitoring with satellite, acoustic and ground-based sensors will help scientists assess geothermal hazards and guide visitor safety in the park.