Yellowstone, USGS release more details about Biscuit Basin explosion

Yellowstone National Park and the U.S. Geological Survey (USGS) issued a joint statement on Wednesday with new information about the hydrothermal explosion that happened at Biscuit Basin in Yellowstone on Tuesday, July 23, 2024.

According to the statement, the explosion occurred as a result of water suddenly transitioning to steam beneath the Black Diamond Pool. The explosion was not caused by volcanic activity.

WATCH THE MOMENT IT HAPPENED: Biscuit Basin explosion captured in tourist video

Visitor footage of "small hydrothermal explosion" in Yellowstone National Park

The statement said that seismicity, ground deformation, and gas and thermal emissions are at normal background levels, and there were no detectable precursors to the explosion on Tuesday.

The explosion sent steam and debris hundreds of feet into the air, according to the statement, destroying a boardwalk and launching "grapefruit-sized rocks" as much as hundreds of feet from their source.

No injuries were reported, despite the close proximity of visitors when the explosion happened.

WATCH MORE: Aftermath of Biscuit Basin explosion revealed in NPS photos

Aftermath of Biscuit Basin explosion revealed in National Park Service photos

The statement said Black Diamond Pool and Black Opal Pool were affected by the explosion and the shape of Black Diamond has "changed somewhat." By Wednesday morning, both were reportedly overflowing and sending murky water into the Firehole River. No water bursts from Black Diamond Pool were witnessed Wednesday morning.

Officials expect that small explosions of boiling water from this area in Biscuit Basin will be possible over the coming days to months. The statement said USGS and NPS geologists will be monitoring conditions, mapping the debris field, and sampling water to assess any changes in the shallow hydrothermal system over the next several days.

Yellowstone National Park has closed Biscuit Basin for the remainder of the 2024 season for visitor safety, according to the statement.