Mount Io is a 512-meter-high active volcano located between Lake Mashu and Lake Kussharo.
Its other name is Atosanupuri, meaning “naked mountain” in Ainu.
In the past, it was used as a mine to extract sulfur.
With the blue sky in the background, the plumes of smoke and the sound of gurgling are quite impressive.
The foot of the mountain is home to large colonies of Marsh tea azaleas.
From mid-June to early July, the pure white flowers blooming all at once is a wonderful sight.
The mountains are also colorfully dyed during the autumn foliage season.
