A New Thermal Pool Emerges in Yellowstone
During the cold months of winter, when snow covered Yellowstone National Park, a mysterious event took place in the Norris Geyser Basin. With limited public access, no one was around to witness what were likely several explosions. However, these events left behind a new thermal pool that has since become a notable addition to the park’s ever-changing landscape.
The newly formed pool is ice-blue in color and warm to the touch. It is roughly the size of a backyard hot tub and is the latest feature to emerge in Yellowstone’s hydrothermal system. Although it has yet to be officially named, its appearance has captured the attention of scientists and visitors alike.
The U.S. Geological Survey (USGS) shared details about this discovery in a recent press release. According to the statement, park geologists first noticed the change when they returned to the Norris Basin in April after the winter season. They were conducting routine maintenance on temperature logging stations when they stumbled upon a surprising sight: a blue water spring that had appeared since the previous year.
This new pool is located in the Porcelain Basin area of Norris, near an informal patch of vegetation known as “Tree Island.” The crater-shaped pool measures about 13 feet across and has a temperature of around 109 degrees Fahrenheit. For comparison, the water from Old Faithful, one of Yellowstone’s most famous geysers, reaches a much hotter 170 degrees Fahrenheit.
Yellowstone sits atop a massive caldera complex, and the geysers, mudpots, vents, and other thermal features that attract millions of visitors each year are all surface expressions of the dynamic hydrothermal system beneath the ground. Due to this constant activity, new events and features like the Norris pool are not uncommon.
In fact, just last summer, a more dramatic incident occurred in Biscuit Basin when an explosion damaged part of the boardwalk and sent a plume of boiling water and boulders into the air. Following the event, Yellowstone National Park closed Biscuit Basin, though no injuries were reported. The area remains closed to this day.
When geologists identified the Norris pool as a new feature, they began investigating how and when it formed. They found rocks coated in light-gray sandy mud, some up to a foot in size, surrounding the pool. These clues suggested a dramatic origin. The USGS press release described the discovery as evidence of a hydrothermal explosion.
To further understand the timeline of the pool’s formation, scientists analyzed high-resolution satellite imagery. The images showed that no feature existed before December 19, 2024. By January 6, a small depression had formed, and by February 14, the pool was fully developed. Infrasound monitoring devices also detected low-level acoustic signals during this time, with the most significant one recorded on Christmas Day of 2024.
However, because seismic signals were not detected, scientists ruled out a major explosion similar to the one in Biscuit Basin. Instead, they concluded that the pool likely formed through multiple small events that initially threw rocks and later silica mud, creating a small pit that filled with silica-rich water.
Naming the New Feature
Yellowstone is home to many unique thermal features, each with its own name. From Anemone Geyser to Mushroom Pool and River Styx, the names often reflect the appearance, location, or activity of the feature. The United States Board on Geographic Names is responsible for officially naming natural features within the park, following specific guidelines.
According to the USGS, thermal features are typically not named after people, a tradition that dates back to the 1870 Washburn Expedition. The ideal names are those that capture the appearance, activity, or location of the feature, while being unique, succinct, and acceptable to local communities.
Hydrothermal explosions and new features in Yellowstone have long fascinated the public. In Norris Geyser Basin, this includes the 1989 eruption of Porkchop Geyser, which sent heated water and rocks into the air. The geyser erupted again in 2003, marking a rare event after many years of dormancy. That eruption was linked to changes in the basin, including the appearance of long fumaroles and increased geyser activity.
More recently, an explosion in April 2024 in the Porcelain Terrace area created a crater several feet wide. As the Norris pool continues to be studied, its eventual name will likely reflect its unique characteristics and the story of its emergence.
