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YELLOWSTONE NATIONAL PARK — Biscuit Basin, a series of pools and geysers within the northwest Wyoming section of Yellowstone National Park, will remain closed to visitors for the rest of the summer following Tuesday's hydrothermal explosion.
Park officials announced the long-term closure Wednesday, explaining that "small explosions of boiling water" are possible "over the coming days to months" because of the impact the explosion had on the basin's hydrothermal plumbing system.
"Yellowstone National Park has closed Biscuit Basin for the remainder of the 2024 season for visitor safety," park officials wrote in a statement.
The section of the park is normally closed during the winter. Other thermal basins in the region, such as Black Sand Basin, are still open to visitors this summer. Grand Loop Road will also remain open to motorists traveling through the park.
No injuries were reported from the massive hydrothermal explosion that happened shortly before 10 a.m. on Tuesday. Boiling water, steam, mud and debris were shot "hundreds of feet" into the air as the water quickly transitioned to steam in a shallow hydrothermal system underneath Black Diamond Pool, National Park Service and U.S. Geological Survey geologists explained on Wednesday.
Videos of the blast — which happened as several park visitors were walking along the basin's boardwalks — swept through social media, garnering millions of views since it happened. They showed visitors running to escape the debris.
![An aerial view of Biscuit Basin within Yellowstone National Park on Tuesday, hours after a hydrothermal explosion.](https://img.ksl.com/slc/3001/300189/30018967.jpeg?filter=kslv2/inline_lg)
A section of the boardwalk in the area was destroyed and some "grapefruit-sized rocks" were found hundreds of feet from where the explosions took place, according to park officials. They released a series of photos and videos showing rocks scattered across the landscape and other aftermath.
"Some blocks closest to the explosion site are about 3 feet wide and weigh hundreds of pounds," they wrote in a lengthy update on the incident. "The explosion was largely directed to the northeast toward the Firehole River and the largest blocks of debris fell in that direction."
The shape of Black Diamond Pool "changed somewhat" after what happened, they added. Both it and Black Opal Pool are now murky because of the debris from the blast. Both started overflowing Wednesday morning, sending some of the murky water into the nearby Firehole River.
National Park Service and U.S. Geological Survey geologists plan to monitor the area, map out the damage and research any potential impacts on the natural wonder. The long-term closure allows time to monitor for any other activity, while park crews repair boardwalk damages.
Hydrothermal explosions are fairly common in this region of the park, typically happening one or multiple times every year, the geologists wrote. Many of these explosions are small or take place in backcountry areas away from where most visitors; however, they added that Tuesday's blast may be most comparable to an explosion by Excelsior Geyser in the Midway Geyser Basin dating all the way back to the 1880s.
Geologists quickly noted on Tuesday that the explosion doesn't "reflect a change in the volcanic system" within the park. The park's volcanic activity remains listed as "normal."
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