Black Diamond Pool Erupts Again in Yellowstone, Second Blast in a Week

Key facts

• Black Diamond Pool erupted on Wednesday, April 29, 2025, just before 12:28 PM.
• This is the second eruption of the pool in a week; the first occurred on Tuesday, April 28.
• The USGS called it 'perhaps the largest eruption of the pool since the 2024 explosion.'
• On July 23, 2024, a hydrothermal explosion destroyed a boardwalk; no injuries were reported.
• A USGS webcam installed on the boardwalk remnant has captured eruptions since 2025.
• There have been three additional eruptions in 2025 before this week's events.
• Wednesday's eruption was the first daytime event not obscured by ice on the camera.

A Second Eruption in Days

The Black Diamond Pool in Yellowstone National Park erupted for the second time in a week on Wednesday, sending plumes of steam and muddy debris hundreds of feet into the air. The U.S. Geological Survey described the event as potentially the largest since a major hydrothermal explosion in July 2024. The eruption occurred just before 12:28 PM local time, according to the agency's webcam footage.

The Largest Since the 2024 Blast

The USGS stated in a social media post that Wednesday's eruption 'is perhaps the largest eruption of the pool since the 2024 explosion and is an important demonstration of hydrothermal hazards in Yellowstone National Park.' The 2024 blast, which took place on July 23 just before 10 AM, destroyed a boardwalk and sent visitors fleeing, though no injuries were reported. Since then, sporadic eruptions have been common, occasionally hurling muddy water tens of feet into the air.

Webcam Captures the Action

Following the 2024 explosion, the USGS installed a camera on the remnant of the destroyed boardwalk to monitor activity at the pool. The webcam has recorded small hydrothermal eruptions since 2025. On Tuesday, April 28, an eruption sent muddy water and steam toward the camera. Wednesday's much larger event was the first daytime eruption captured without the lens being covered by ice.

A Pattern of Activity

The Black Diamond Pool has been unusually active this year. Prior to this week's back-to-back eruptions, there had been three additional eruptions in 2025. The pool's behavior underscores the dynamic geothermal forces beneath Yellowstone, one of the world's largest active volcanic systems. The USGS continues to monitor the area closely.

Ongoing Hazards and Access Restrictions

The Biscuit Basin Trailhead area, near the Black Diamond Pool, remains closed until further notice due to the July 2024 explosion. The USGS warns that hydrothermal hazards persist, and visitors are advised to stay on designated paths. The agency's webcam provides a live feed of the pool for public viewing.

What Comes Next

Geophysicist Michael Poland of the USGS has explained that hydrothermal explosions like these are driven by sudden pressure releases from underground steam and hot water. While such events are localized, they serve as reminders of the park's volatile geology. The USGS will continue to analyze data from the webcam and seismic instruments to better understand the pool's behavior.

The bottom line

• Black Diamond Pool erupted twice in one week, with Wednesday's blast being the largest since 2024.
• The USGS webcam, installed after the 2024 explosion, captured both eruptions.
• from any of the recent eruptions.
• The Biscuit Basin Trailhead remains closed due to ongoing hazards.
• Yellowstone's geothermal activity is closely monitored, but hydrothermal explosions can occur without warning.