A small hydrothermal explosion rocked Yellowstone National Park’s Biscuit Basin on June 13 at about 5:09 a.m. local time, sending hot water and sediment into the Firehole River and creating new vents and a new boiling pool. No injuries were reported because th
For the third time in a matter of hours. Yellowstone’s underground thermal system changed the surface as if it were drawing a new map. On June 13. just after 5 a.m. an explosion in Biscuit Basin sent a milky plume downstream through the Firehole River—followed by new vents where solid ground had existed only days earlier.
The U.S. Geological Survey’s Yellowstone Volcano Observatory said the small hydrothermal explosion occurred at about 5:09 a.m. local time on June 13. No injuries were reported. Biscuit Basin has remained closed since a much larger hydrothermal explosion near Black Diamond Pool in July 2024.
What came next was visible, measurable, and unsettling. The blast created new vents and drove hot water and sediment into the Firehole River. Within days, a new boiling pool formed in an area that had been solid ground.
Monitoring stations and cameras helped piece together the timeline. Equipment detected unusual seismic activity and low-frequency acoustic signals—known as infrasound—coming from the direction of Black Diamond Pool shortly after 5 a.m. on June 13. Later that morning. park staff noticed something unusual: a light-gray. milky plume flowing through the Firehole River downstream from Biscuit Basin. They also observed new runoff channels leading from the basin into the river.
A camera installed in 2025 captured the disturbance as well, recording a dark-colored steam plume erupting from the ground north of Black Diamond Pool at nearly the same time the monitoring equipment registered the event.
When geologists arrived the following day, they found three groups of newly formed vents. Geothermal water near boiling suddenly reached the surface, and as it rapidly turned to steam, it triggered the hydrothermal explosion.
The newly formed landscape left behind precise clues. One crack north of Black Diamond Pool stretched about 61 feet long and up to 5 feet wide. Another vent measured roughly 49 feet long. Water temperatures in the area ranged from 185 to 200 degrees Fahrenheit, near the boiling point at Yellowstone’s elevation.
The explosion itself was considered relatively small. Rocks thrown from the vents landed only a few yards away, suggesting far less force than the July 2024 explosion.
Geologists returned days later and discovered an entirely new pool measuring about 21 feet by 17 feet. It was filled with gray, silty water and vigorously boiling. The pool also produced loud thumping sounds as steam bubbles formed and collapsed beneath the surface.
Camera footage recorded June 18 showed the pool occasionally spouting water 20 to 30 feet into the air before settling back into active boiling.
Hydrothermal explosions happen when pressurized hot water trapped underground suddenly flashes into steam. Smaller than volcanic eruptions, they can still be extremely dangerous—especially because they often occur with little warning.
That’s why scientists are paying close attention to June 13. Researchers installed temporary seismic monitoring stations in Biscuit Basin and are analyzing data collected before the explosion. Because the event occurred only about 328 feet from a monitoring station installed in 2025. scientists believe they may have captured valuable clues about whether warning signs were present beforehand.
The June 13 explosion is being described by researchers as an unprecedented opportunity to better understand hydrothermal hazards at Yellowstone and potentially improve future detection efforts.
The park’s deeper geology remains the backdrop to every alarm and every image. The U.S. Geological Survey says Yellowstone sits on top of a large volcanic system called the Yellowstone Caldera. Heat from magma deep underground fuels the park’s geysers. hot springs and other hydrothermal features by heating groundwater circulating beneath the surface.
Despite public concern, the U.S. Geological Survey says the system is not “overdue” for a major eruption. The agency points out that volcanic activity does not follow predictable schedules and says there is no evidence an eruption is imminent.
What happened at Biscuit Basin on June 13 left Yellowstone with fresh scars—and gave scientists a rare, close-up chance to test how much the ground can reveal before it erupts.
Yellowstone Biscuit Basin hydrothermal explosion Firehole River U.S. Geological Survey Yellowstone Volcano Observatory infrasound geothermal hazards magma caldera monitoring stations