Overview
- A small hydrothermal explosion occurred at Biscuit Basin on June 13, 2026, with seismic and infrasound sensors and a Yellowstone Volcano Observatory camera recording a dark jet of water at 5:09 a.m.
- Geologists found three newly formed vent groups that funneled large volumes of near‑boiling water into the Firehole River, producing a linear crack about 61 feet long and up to 5 feet wide.
- A collapse-created pool about 21 by 17 feet formed between June 14 and 16 and was observed roiling and intermittently spouting water 20 to 30 feet high on June 18.
- Measured water temperatures in the new features ranged from roughly 185°F to 200°F, no injuries were reported, Biscuit Basin has remained closed since the July 23, 2024 explosion, and temporary seismic stations were installed to track changes.
- Officials say the sequence highlights how underground hot water can suddenly flash to steam, why continuous camera, seismic and infrasound monitoring matter for visitor safety, and why closed thermal areas must be respected.