YELLOWSTONE NATIONAL PARK – On April 10, 2025, geologists with Yellowstone National Park were conducting routine maintenance at Norris Geyser Basin when they spotted a new blue water spring. The new pool was found in the Porcelain Basin subbasin, just west of an area of vegetation known as “Tree Island”.
The new pool measures around 13 feet across and the water sits at a temperature around 109°F. It’s light blue in color and the water is about a foot below the rim. Numerous small rocks up to about a foot across were found around the pool, covered by light-gray, fine grained sandy mud.
That discovery, along with the discovery of two layers exposed on the side of the pool with the lower “layer” being just a coating left of the steep side of the pool what the water level was high, showed scientists that they had found the remains of a hydrothermal explosion.
Explosions in the Norris Geyser Basin are not necessarily surprising as the thermal basin has been the site of many events like this. Based on multiple sets of data collected from a series of different tools, this pool did not form in one major explosive event like the massive one that occurred in July of 2024 in Biscuit Basin.
Instead the new pool was likely formed through multiple small events, initially throwing rocks and later throwing silica mud a short distance to create the small pit that wound up filled with silica-rich water. It likely started to develop on December 25, 2024, and continued to grow with activity in mid-late January and early February of this past winter.
