Impression Photo Black Diamond Pool, Yellowstone National Park

"Black Diamond Pool, Biscuit Basin, Yellowstone National Park, Wyoming" by Catherine Sherman. A bright blue geothermal hot spring is surrounded by mineral deposits and a steamy mist, set against a forested backdrop with a bright blue sky and scattered clouds. Black Diamond Pool, cerulean blue geothermal hot spring in Biscuit Basin, is surrounded by mineral deposits and a steamy mist, set against a forested backdrop with a bright blue sky and scattered clouds in this photograph taken September 9, 2022. Biscuit Basin is a collection of hot springs that lie a few miles north of Old Faithful Geyser in Yellowstone National Park, Wyoming. A hydrothermal explosion happened around 10 a.m., July 23, 2024, in Black Diamond Pool Biscuit Basin, sending the tourists on the boardwalk running. The explosion sent steam and debris "hundreds of feet above the ground," according to the National Parks Service. A boardwalk was destroyed, nearby trees were killed, and "grapefruit-sized rocks" were thrown into the air. Some blocks of debris weigh hundreds of pounds and are about 3 feet wide, the NPS said. No one was hurt in the explosion, though visitors were in the area. Similar blasts have happened in Biscuit Basin in 2009, 1991 and after the magnitude 7.2 Hebgen Lake earthquake 40 miles (64 kilometers) away in 1959. Black Diamond Pool and neighboring Black Opal Pool were murky and overflowing. The excess water ran into the Firehole River. Biscuit Basin was closed for the rest of the 2024 summer.