YELLOWSTONE NATIONAL PARK — Biscuit Basin in Yellowstone National Park (YNP) continues to detonate with hydrothermal activity.
According to this week’s installation of Caldera Chronicles, a small hydrothermal explosion took place in Biscuit Basin, not far from Black Diamond Pool, in the early morning of Saturday, June 13. Black Diamond Pool was the location of a famous July 2024 hydrothermal explosion. The scientists and collaborators of the Yellowstone Volcano Observatory (YVO), who wrote this week’s column, say that the recent explosion was much smaller than the initial blast, but it emphasizes the “dynamic and hazardous nature” of the region’s hydrothermal activity. Nobody was impacted by the phenomenon, as the area has remained closed to the public since 2024.
After the first major explosion in Biscuit Basin, YVO scientists installed a camera and monitoring equipment in the area to record possible future activity. The column states that this gear registered seismic energy and a low-frequency acoustic signal near Black Diamond Pool just after 5 a.m. on June 13. As the sun rose that day, park staff noticed two runoff channels from Biscuit Basin to the Firehole River that had not existed before. Due to the water and sediment coming from these channels, a section of the river had turned gray and milky.
Monitoring equipment indicated that the activity did not come from Black Diamond Pool, but the camera in the area had recorded a plume of steam just north of Black Diamond. When YNP geologists visited the scene, they found evidence of large amounts of hydrothermal water and three new vent groups.
“These vents represent pathways where water at or even slightly above boiling temperatures beneath the ground suddenly found a pathway to the surface and flashed to steam, driving a hydrothermal explosion,” reads Caldera Chronicles.
Two days later, the Yellowstone Geology Program returned to find a new pool near the recently discovered vents. Right in the area where the team had been walking, just days before, was an actively boiling pool with silty, gray water. The 21-by-17-foot pool was not surrounded by explosion debris, which means it likely formed by collapsing, noted the writers of Caldera Chronicles.
On Thursday, June 18, recorded observations showed the new pool experiencing geyser-like behavior with intermittent spouting to a height of 20 to 30 feet. YVO scientists have since installed temporary seismic monitoring stations in the area to record the evolution of the newly formed vents. Scientists will continue to look at data to determine whether there were any signals that could have warned of the eruptions. No hydrothermal explosion has taken place this close to a monitoring station before, according to the column.
“The recent explosion emphasizes the unstable and hazardous nature of some of Yellowstone’s thermal areas,” reads Caldera Chronicles. “Biscuit Basin, and especially the area around Black Diamond Pool, has been a site of numerous hydrothermal explosions for more than a century. … The June 13, 2026, explosion thus offers an unprecedented opportunity to better understand this critical hazard in Yellowstone National Park and perhaps learn more about their potential warning signs.”
