If you are planning on driving in Yellowstone National Park when most of its roads open in April, you could drive by one of the latest thermal steam vents in the famed hotspot. The new hydrothermal feature is about one mile north of the Norris Geyser Basin within a region called the Roadside Springs thermal area.  According to the United States Geological Survey (USGS), the Roadside Springs thermal area is a collection of distinct areas of altered rock and hydrothermal features. The new steam vent is at the foot of a rhyolite lava flow almost 10 feet above the marshland below and is part of an area of warm, hydrothermally altered ground roughly 200 feet long. It was initially spotted by park scientists during last summer’s busy tourist and seismic season in the park. July saw a hydrothermal explosion at Biscuit Basin and a similar explosion was recorded in Norris Geyser Basin for the first time.  “While driving south from Mammoth Hot Springs towards Norris Geyser Basin early on August 5 last summer, a park scientist noticed a billowing steam column through the trees and across a marshy expanse,” scientists from the USGS’s Yellowstone Volcano Observatory wrote in a recent blog post. “The eagle-eyed scientist notified the park geology team to verify if this was indeed new activity.” Geologists then trudged through the marsh to get a closer look at the balmy 171 degrees Fahrenheit hydrothermal feature. By a thin layer of gray silica clay, they could tell that this steam vent is rather young.  Looking southeast at the hydrothermal feature that formed in August 2024 just north of Nymph Lake. Steam is emanating from a vent that is partially full of water to create the frying pan feature nestled in the newly formed vent. A thin grey layer of silica mud covers the vent area.  CREDIT: Photo by Jefferson Hungerford, Yellowstone National Park, August 2024. “The feature itself is new. That there would be a new feature is, you know, mundane,” park scientist Mark Polland told the Associated Press. “The noteworthy part … was just that it was so noticeable. But the sort of overall idea that there would be a new feature that formed is pretty normal.” The team believes that it is the latest formation in a hotspot located only a short distance away that bubbled up over 20 years ago. A similar type of hydrothermal activity was observed on the other side of this same lava flow on March 10, 2003. The activity there has continued over the years, but is less energetic than when it first formed. This new steam vent remained active into the fall of 2024 and the strong steam plume was particularly visible during chilly mornings.  An aerial view looking to the west at the Roadside Springs hydrothermal area and Nymph Lake showing the locations of thermal features that formed in 2003 and 2024. The yellow line marks the Mammoth-Norris highway. CREDIT: Figure by Jefferson Hungerford, Yellowstone National Park. “But as fall began to turn into winter, the steam plume gradually disappeared. The feature remains active, but there is some water in the vent, decreasing the amount of steam that is released,” the USGS said. “Whether or not the strong plume returns in the summer of 2025 remains to be seen.” Yellowstone National Park geologists have mapped more than 100 major hydrothermal areas in and estimate that there are over 10,000 additional hydrothermal features within its boundaries. The post Keep an eye on Yellowstone’s steamy new hydrothermal vent appeared first on Popular Science. ...read more read less