Roaring Mountain, Thermal mountain in Yellowstone National Park, United States

Roaring Mountain is a rhyolite hill of 8,152 feet (2,485 m) in Yellowstone National Park, Wyoming, 5 miles (8.0 km) north of Norris Geyser Basin. Its western slope holds numerous fumaroles venting steam and gases at about 92 °C, and the very acidic deposits leave the ground around them bare of plants.

Roaring Mountain was first documented in 1885 by geologists Arnold Hague and Walter Weed. Hague gave it its name because its fumaroles produced a drawn-out, sharp whistle audible for many miles on clear, windless days. The vents were loudest in the early 1900s, when they could be heard for several miles; activity is now much weaker than at the start of the 20th century.

The name "Roaring Mountain" was given by geologist Arnold Hague, who with Walter Weed explored the feature in 1885; Hague chose it for the drawn-out, sharp whistle the fumaroles made on clear, windless days. The Polish source notes the gases and steam escape at about 92 °C.

The easiest view is from a wheelchair-accessible overlook with informational displays, located right at a large parking area along the road between Norris and Mammoth Hot Springs. You can spend as little or as much time here as you want, and everything is clearly visible from the pullout.

Roaring Mountain's fumaroles were loud enough in the early 1900s to be heard several miles away; today the mountain is far less active. Geologists Arnold Hague and Walter Weed came upon it in 1885, and Hague gave the name because of the long, sharp whistle the vents made on clear, windless days.