A violent eruption of a Yellowstone National Park thermal feature Tuesday blew up a boardwalk and sent visitors scrambling to escape a powerful explosion of black water, mud and rocks.
Black Diamond Pool in the park’s Biscuit Basin erupted at 9:45 a.m., ejecting an immense amount of black water onto a nearby boardwalk, destroying it, and sending tourists running for their safety.
According to GeyserTimes, a radio message from the National Park Service reported a "large explosion" with "lots of debris (and) no injuries."
Biscuit Basin was closed after the eruption.
Sapphire Steam And Black Diamond Debris
The March family vising from California was touring the Biscuit Basin when Black Diamond Pool erupted. Steve and his wife, Vlada, were on the boardwalk with their two sons, Vlada's mother, and Issac Fischer, their guide from Casanova Guided Tours.
They had a video camera running at the time, capturing the spectacular eruption even as they retreated to a safe distance. Other visitors also are seen fleeing the violent thermal spew.
Steve March told Cowboy State Daily that the only indication something was brewing under Biscuit Basin was a large amount of steam emanating from the Sapphire Pool.
"We were walking toward Jewel Geyser when our guide pointed out the steam that suddenly shot out of Sapphire Pool," he said. "I guess that's never been witnessed before. And literally, a moment later, there was this massive explosion and a massive amount of rock (from Black Diamond Pool).”
Steve described the eruption of Black Diamond Pool as "a mushroom cloud" of black water and hard debris launched "hundreds of feet" into the air.
Biscuit Basin was suddenly filled with cries of fear and panic as people on the boardwalk started running along the narrow span away from the explosion.
"Our guide told us to run," Steve said. “So, we grabbed our kids, and we made our way to solid ground as soon as we could. Then we (realized) that we weren't sure about my mother-in-law's status. She's not very mobile and could have been hit by one of those rocks."
The family quickly reunited with Vlada's mother.
She was unhurt, but Steve said his mother-in-law was covered head to toe in mud and silt ejected from Black Diamond Pool.
After a few seconds, the eruption was over.
A Warzone
Steve said the aftermath resembled a warzone, with the Black Diamond Pool looking like a muddy crater surrounded by black mud and chunks of rock.
Steve said the explosion was so intense that it destroyed sections of the Biscuit Basin boardwalk.
"You could see pieces of wood sticking out and the ground underneath where you're not supposed to see it," he said. "The boardwalk covered in dirt, silt and rocks."
Yellowstone rangers arrived within five minutes of the eruption and closed the area.
Steve and Fischer gave eyewitness accounts to the rangers before departing the area.
"It was a unique experience, to say the least," Steve said.
Black Diamond Pool (And Geyser)
According to the NPS, Black Diamond Pool has been infrequently erupting since an earthquake in 2006. Inactive since 2016, the pool has erupted twice in 2024, with the last eruption on May 7.
Black Diamond Pool was formed after a hydrothermal explosion in the Biscuit Basin. It usually appears full of murky blue water that overflows into several surrounding pools. The pool has an average temperature of 148.5 degrees and an average pH of 8.2, which is in the same basic acidic range as seawater.
Contact Andrew Rossi at arossi@cowboystatedaily.com
Andrew Rossi can be reached at arossi@cowboystatedaily.com.
