"The pool formed via collapse, indicated by the absence of surrounding ejecta."
June 2026 Hydrothermal Explosion Creates New Boiling Pool at Yellowstone's Biscuit Basin
A new pool of boiling water emerged near the middle vent group at Biscuit Basin in Yellowstone National Park between June 14 and June 16, 2026—just days after a hydrothermal explosion rocked the area.
The Event
The U.S. Geological Survey (USGS) reported that a small hydrothermal explosion occurred at 5:09 a.m. local time on June 13, 2026, less than 2 miles northwest of Old Faithful. No injuries were reported.
Monitoring recorded anomalous seismic and infrasound signals from the Black Diamond Pool area, where a previous hydrothermal explosion occurred on July 23, 2024.
New Vent Groups and Pool Formation
The explosion opened three new vent groups: northern, middle, and southern.
- The northern vent included a crack about 61 feet long and up to 5 feet wide, surrounded by ejected rocks.
- The new pool—described as gray and silty—formed near the middle vent group via collapse, confirmed by the absence of surrounding ejecta.
- Camera observations on June 18 showed intermittent spouting up to 20-30 feet from the new pool.
Environmental Impact
Park rangers observed a light-gray to milky runoff in the Firehole River downstream from Biscuit Basin. Geologists found that large volumes of hydrothermal water had surged into the river from the three newly formed vent groups. Water temperatures at the vents ranged from 185°F to 200°F.
Context and Safety
- View is to the southeast, with Black Diamond Pool in the right middle ground and the Firehole River in the background.
- Biscuit Basin has been closed since the 2024 explosion, so no one was affected by this latest event.
- A camera installed in 2025 recorded a dark-colored stream jetting from the ground north of Black Diamond Pool.
- Temporary seismic stations have been installed to monitor vent evolution.
"Large volumes of hydrothermal water surged into the Firehole River from three newly formed vent groups."