YELLOWSTONE NATIONAL PARK — According to the Yellowstone Volcano Observatory’s (YVO) latest Caldera Chronicles, a new hydrothermal feature popped up in Yellowstone National Park (YNP) in the summer of 2024.
Jefferson Hungerford of YNP writes that a park scientist driving south from Mammoth Hot Springs toward Norris Geyser Basin early on Aug. 5 noticed a billowing steam column through the trees and alerted the park geology team to the new activity.
According to Hungerford, the new hydrothermal feature is within a region called the Roadside Springs thermal area, at the foot of a rhyolite lava flow; soon after it was identified, park geologists determined the feature had a temperature of 77°C (171°F). Hungerford writes that a very thin veneer of grey silicious clay barely covered the surrounding surface, indicating the feature’s very young nature.
On March 10, 2003, Hungerford confirms that a similar type of hydrothermal activity was observed for the first time on the other side of the same rhyolite lava flow where the new feature is located, just west of Nymph Lake.
“This hydrothermal activity persists through this day but is much less energetic than when it first formed,” Hungerford writes. “Are the new feature and the activity that started in 2003 hydrologically connected? Probably.”
The new feature remained “prominent” into the fall of 2024, Hungerford writes, with a strong steam plume especially visible during chilly mornings. But, as fall began to turn into winter, Hungerford confirms the steam plume gradually disappeared. While the feature remains active, the amount of steam released has decreased.
“Whether or not the strong plume returns in the summer of 2025 remains to be seen,” Hungerford writes.
