Ōyunuma

(1) Underneath the smoky Mount Hiyori, hollows at the bottom of Oyunuma heat the lake water to 130 degrees Celsius and release poisonous hydrogen sulfide gas (surface temperature is about 50 C). (2) Okonoyu, a dusty black sulfur spring with a surface temperature around 80 C. (3) Oyunuma Brook Natural Footbath—a good rest stop for hikers to soak in the elements from the hot spring.Read more