Hydrothermal Explosion Causes Damage in Yellowstone National Park

A hydrothermal explosion inside Yellowstone National Park sent rocks and debris flying Tuesday morning, damaging a pedestrian boardwalk and forcing the closure of the area.

The explosion occurred at the Biscuit Basin thermal area around 10 a.m. local time, appearing to originate near the Black Diamond Pool, according to the U.S. Geological Survey. Biscuit Basin, as well as its boardwalks and parking lots, are closed for visitor safety as park geologists investigate what occurred, the USGS reported. The popular tourist spot is located roughly two miles northwest of Old Faithful.

Michael Poland, the scientist-in-charge at the U.S. Geological Survey’s Yellowstone Volcano Observatory, said in an information statement early Tuesday afternoon that there had so far been no injuries reported in the explosion.

“Monitoring data show no changes in the Yellowstone region. Today’s explosion does not reflect activity within the volcanic system, which remains at normal background levels of activity,” Poland said in the statement.

“Hydrothermal explosions like that of today are not a sign of impending volcanic eruptions, and they are not caused by magma rising towards the surface.”

He explained that these types of explosions happen when water quickly changes to steam underground and they are “relatively common” in Yellowstone National Park. There was a similar explosion in Biscuit Bay in May 2009 and a smaller explosion in Norris Geyser Basin on April 15. Porkchop Geyser in Norris Geyser Basin exploded in 1989.

Taking place as often as twice a year, frequently in the backcountry, hydrothermal explosions can go undetected other than by monitoring equipment, according to Mr. Poland. This explosion, however, was fully documented by tourists with smartphones.

“It’s really quite dramatic,” Mr. Poland said of the footage.

Facebook user Vlada March, who posted the video, wrote on the platform that the explosion occurred right in front of her and her family. Ms. March said about her mother, “she was covered in ash, head to toe,” after looking for her frantically and shouting for her two young sons to run away.

“Boardwalk destroyed, my mom got some of the debris but everyone is safe. Unbelievable and grateful to be alive,” March stated.