Yellowstone’s Biscuit Basin to remain closed for the rest of summer following explosion

YELLOWSTONE NATIONAL PARK, Wyo. (KIFI) — Yellowstone Park officials said Biscuit Basin will remain closed for the rest of the 2024 season.

The decision was made as a safety measure for visitors given the recent changes caused by a hydrothermal explosion on Tuesday.

Park officials said the hydrothermal explosion at Biscuit Basin resulted from water suddenly transitioning to steam in the shallow hydrothermal system beneath Black Diamond Pool. They said it was not caused by volcanic activity.

The explosion, which sent steam and debris to a height of hundreds of feet above the ground, destroyed the nearby boardwalk and ejected grapefruit-sized rocks tens to hundreds of feet from the source. They reported some blocks closest to the explosion site are about 3 feet wide and weigh hundreds of pounds. The explosion was largely directed to the northeast toward the Firehole River, and the largest blocks of debris fell in that direction. They said the dark color of the explosion was a result of mud and debris mixed with steam and boiling water. Although visitors were present at the time of the event, no injuries were reported.

Black Diamond Pool and Black Opal Pool were affected by Tuesday’s explosion, and while they remain distinct features, the shape of Black Diamond has changed somewhat. Both pools are murky due to debris, and the unstable ground around their edges occasionally slides into the water. Just after the eruption, Black Diamond Pool exhibited minor roiling and water spouting. The water level in the pool rose over the course of the day, and by Tuesday afternoon the roiling transitioned to occasional bursts of hot water that reached about 8 feet in height.

Park officials said by Wednesday morning, July 24, the levels of Black Diamond Pool and Black Opal Pool had risen enough that both were overflowing and sending murky water into the Firehole River. No water bursts from Black Diamond Pool were witnessed Wednesday morning.