Another hydrothermal explosion at Biscuit Basin (Yellowstone Monthly Update - June 2026)

On June 13, 2026, Yellowstone National Park’s newest geophysical monitoring sites captured a small hydrothermal explosion in Biscuit Basin! That story is the subject of this month’s video update.

On July 23, 2024, Biscuit Basin was the site of a significant hydrothermal explosion. Just before 10 am that day, an explosive event from Black Diamond Pool sent rocks flying, destroying a nearby boardwalk but fortunately not causing any injuries. The explosion was caused by pressure changes in the hot water plumbing system just beneath the surface, with hot water flashing to steam and driving the activity. To monitor the area, the Yellowstone Volcano Observatory installed several new sensors after the explosion. On June 13, 2026, that monitoring equipment detected significant seismic and acoustic energy, with video observations catching a jet of steam coming from new features that opened several hundred feet to the north of Black Diamond Pool.

The explosion wasn’t nearly as large as the 2024 event but still had enough energy to throw rocks several tens of feet and break open the earth. One crack was 60 feet long and full of boiling water. A day or two later, a portion of the ground in the vent area had collapsed into a circular pool that was filled with boiling water. On June 18, the camera caught that pool spouting almost like a geyser, and on June 23 it erupted in a single burst that sent steam and boiling water up several tens of feet.

Biscuit Basin remains closed to visitors because of the damage to the boardwalk and the potential for hazardous and unpredictable activity.

During the month of June 2026, the University of Utah Seismograph Stations, which monitors and operates the Yellowstone seismic network, located 118 earthquakes; the largest was a Magnitude 2.4. There has been no significant uplift or subsidence of the caldera since January 2026. Echinus Geyser had one water eruption in June, Giant Geyser erupted for the first time since last October, and Fan and Mortar Geyser had its first eruption in about 3 years! Yellowstone volcano remains at normal, background levels of activity.

For questions, email yvowebteam@usgs.gov

Read Caldera Chronicles https://www.usgs.gov/volcanoes/yellowstone/caldera-chronicles

Visit Yellowstone Volcano Observatory website https://www.usgs.gov/volcanoes/yellowstone