Biscuit Basin, about two miles northwest of Old Faithful, has been temporarily closed due to a hydrothermal explosion that occurred around 10:20 a.m. Tuesday near Sapphire Pool, according to a park news release. No one was injured and the park is assessing the damage. Photos accompanying the news release show staff examining broken railings and blackened debris on the boardwalk.
In a video shared by The Washington Post, March can be heard yelling at her family to “run, run, run!” as others flee the cloud that is rising over the boardwalk.
March and her husband, Steve, were worried one of their children would fall and become trapped while fleeing the explosion.
March’s sons, Maxwell, 9, and Ethan, 6, had never been to a national park before. They were most worried about their grandmother, March said. March’s mother, Natalia, was closest to the explosion and had her jacket covered in mud.
March said about 30 people were in the area at the time of the explosion.
The tour guide told March that the explosion went at least 200 feet into the air.
Parking lots and trails around the area will remain closed for “safety reasons,” according to a news release. Park staff and U.S. Geological Survey staff plan to reopen the area when it is safe to do so.
A hydrothermal explosion occurs when hot water creates bubbles of steam, building up underground pressure and eventually bursting through the surface, much like steam building up inside a sealed pressure cooker, said Ken Sims, a geology professor at the University of Wyoming and a member of the Yellowstone Volcano Observatory.
“Eventually it’s going to release a lot of steam and explode,” Sims said.
The explosion does not reflect a change in the volcanic system, and “no changes have been observed in other monitoring data in the Yellowstone region,” the park’s statement said.
Sims said the volcanic and hydrothermal systems are separate.
“These kinds of explosions are common, and that’s what makes Yellowstone so special,” Sims says. “If it was magma, you’d have big changes in the ground, deformation, gas release, everything. But this was an isolated ball of steam that exploded in the ground.”
