Roaring Mountain in Yellowstone National Park no longer lives up to its name the way it once did, but do not mistake its relative silence for calm. The thermal feature, located between Norris Geyser Basin and Mammoth Hot Springs, was once so loud that visitors could hear its hissing fumaroles from four miles away at Obsidian Cliff. It quieted for a period, then roared back to life in 1902, and has been comparatively subdued ever since.
The ground at Roaring Mountain remains intensely hot, with many features reaching boiling temperature. The thermal area is so hot it is visible from space. Nearby hydrothermal explosion craters add to the area’s volatile character, including Semi Centennial Geyser, which exploded in 1922, and several additional craters located roughly half a mile up on the plateau above the mountain.
Mike Poland, the USGS Yellowstone Volcano Observatory‘s Scientist-in-Charge, discussed Roaring Mountain in the most recent Yellowstone Monthly Update, in addition to recent regional seismicity, ground deformation, and geyser activity.
Seismicity across Yellowstone remained average for the month, with 97 earthquakes recorded by University of Utah seismograph stations. The largest was a magnitude 2.5 near Norris Geyser Basin. Activity was spread throughout the region, with a notable concentration between Hebgen Lake and the north-central portion of the park.
Ground deformation data from the Lake GPS site shows the caldera has largely been in a subsidence trend since 2015, with typical summertime uplift due to groundwater changes. That expected transition back to subsidence in late 2025 and early 2026 did not materialize clearly, and winter storms have complicated the data. Net change over recent months has been minimal.
On the geyser front, Steamboat Geyser has been showing increased minor activity, which could signal a major eruption this summer. Echinus Geyser erupted four times in April. Black Diamond Pool, site of a hydrothermal explosion in July 2024, produced two eruptions on April 28th and 29th, with the April 29th event being the largest recorded since monitoring equipment was installed in summer 2025.
