Tuesday, July 23, at about 10:19 a.m., Yellowstone National Park (YNP) experienced a localized hydrothermal explosion near Sapphire Pool in Biscuit Basin, just a couple miles northwest of Old Faithful.
A cloud of sooty black steam shot up into the sky, sending tourists running as debris hailed down. Most of the time tourists are seen running in Yellowstone, it’s because they didn’t respect the local’s personal space—but the tourists were at no fault here. This was a random, yet totally natural and normal geothermal event.
Fortunately, there were no reports of injury. The boardwalk, however, in very close proximity to the explosion, experienced some extreme damage.
According to a press release from the USGS, hydrothermal explosions are relatively common in Yellowstone. They occur when water suddenly flashes to steam underground. In fact, a similar event occurred in Biscuit Basin on May 17, 2009. Additionally, Porkchop Geyser, in Norris Geyser Basin, experienced an explosion in 1989, and a small event in Norris Geyser Basin was recorded by monitoring equipment on April 15, 2024.
Folks often ask the Yellowstone Volcano Observatory (YVO) when “the next big one” is going to happen. But that could mean a few different things. Is it the next big earthquake, lava flow, or eruption? According to the YVO, a big explosion isn’t very likely, but hydrothermal explosions are.
“Hydrothermal explosions are violent and dramatic events resulting in the rapid ejection of boiling water, steam, mud, and rock fragments,” YVO stated. “The explosions can reach heights of 1.2 miles and leave craters that are from tens of feet up to more than 2 1.2 miles in diameter.”
This video, captured by YouTube user Michael Whitman, demonstrates just how striking the explosion was.
Tourists were sent running to avoid the debris ejected from the earth during the event.
This clip, posted by FaceBook user Vlada March, shows the aftermath of the explosion and people quickly evacuating the area.
According to USGS and YNP, the explosion does not reflect any significant change in the Yellowstone volcanic system, which remains at normal background levels of activity. However, YNP has issued a temporary closure of Biscuit Basin, but park and USGS staff will monitor conditions and reopen the area once deemed safe.
Feature image on left via Vlada March Facebook video, right image via YNP.