This image made from video provided by the United States Geological Survey (USGS) shows a muddy eruption at Black Diamond Pool in Yellowstone National Park on Saturday, Dec. 20, 2025. (U.S. Geological Survey via AP)
December 21, 2025 - 12:33 AM
“Kablooey!”
That's the word U.S. Geological Survey volcanic experts used to describe a muddy eruption at Black Diamond Pool in Yellowstone National Park on Saturday morning.
Video shared by the USGS on social media shows mud spraying up and out from the pool just before 9:23 a.m. in Biscuit Basin about midway between park favorites Old Faithful and Grand Prismatic.
Other recent eruptions have mostly been audible and not visible, because they happened either at night or when the camera was obscured by ice.
The agency said the Black Diamond Pool was previously the site of a hydrothermal explosion, in July 2024, that sent rocks and mud flying hundreds of feet high and damaged a boardwalk. It prompted the closure of the area to visitors due to the damage and the potential for additional hazardous activity.
So-called dirty eruptions reaching up to 40 feet (about 12 meters) have occurred sporadically since then.
Researchers installed a new camera and a seismic and acoustic monitoring station this summer, and they say the instruments, along with temperature sensors maintained by the Yellowstone National Park Geology Program, can better detect and characterize the eruptions.
The Yellowstone Volcano Observatory webcam at Black Diamond Pool didn't disappoint Saturday.
“We got a nice clear view of one of these dirty eruptions under bright blue skies with the surroundings covered in snow (ah, winter in Yellowstone!),” USGS Volcanoes said on social media, noting that it was a great example of the kind of activity that has been happening at the spot over the past 19 months.
Experts say there is no real pattern to the eruptions at the pool and no precursors.
Park officials say Yellowstone preserves the most extraordinary collection of hot springs, geysers, mud pots and fumaroles on Earth. More than 10,000 hydrothermal features are found within the park, over 500 of them geysers.
News from © The Associated Press, 2025