The Echinus Geyser at Yellowstone National Park, which is the biggest acidic geyser on the planet, has been “wowing” visitors due to a reawakening that is both a rare gem and striking view.
Situated in the Norris Geyser Basin’s Back Basin, the geyser surprisingly erupted Feb. 7 following approximately six years of being inactive, recording the first eruption since Dec. 2020. Follow-up bursts occurred Feb. 9, 12 and 15.
According to the U.S. Geological Survey (USGS), the geyser’s activity amplified Feb. 16, as eruptions took place every 2-5 hours.
The USGS highlighted that acid geysers are rare due to acidic water being able to break down rock making up the plumbing system of a geyser. (RELATED: Millions In Central US Face Multi-Day Severe Weather With Risks Of Tornadoes, Hurricane-Force Winds, Flooding, Hail)
“At Echinus Geyser, however, the composition is due to mixing between acidic gases and neutral waters, and the acidity is not sufficient to eat away at the rock,” states the USGS.
The unique water composition of the geyser triggers mineral formations that are distinct.
A radiant red edge of arsenic, iron and aluminum encircles the pool, with the thorny, silica-covered rocks disbanded close by providing the inventiveness for the name of the geyser.
For the first time since 2020, Echinus Geyser (Norris Geyser Basin, Yellowstone National Park) is erupting! Caldera Chronicles has the details about the show. https://t.co/Ml6NOqyw2W
📷1: Echinus Geyser, seen from above in a photo taken by a research balloon in 2005. The… pic.twitter.com/z4GyqW8xNd
— USGS Volcanoes🌋 (@USGSVolcanoes) March 2, 2026
With a timeframe of around 2-3 minutes, the height of eruptions can reach approximately 20-30 feet.
The water level of the pool declines significantly and needs around one hour to get refilled after the conclusion of the eruption.
During its prime decades ago when there was higher activity, there were differences in eruptions, ranging from small ones to bigger ones stretching up to 75 feet.
It’s noted by the USGS that every eruption occurred in February from the middle to the end of the month. Since Feb. 24, there haven’t been anymore eruptions. (RELATED: Rural Nevada Shook By Magnitude 4.3 Earthquake)
Currently, it’s uncertain whether or not there will be a continuance of activity into the summer, which would allow more tourists to witness the sight.
However, due to history showing Echinus having active phases that only last 1-2 months, an extended return is seemingly doubtful.
With that being said, as the Norris Geyser Basin continuously shifts, an opportunity always exists for activity to restart, per the USGS.