KAMISHIHORO, Hokkaido — A “mushroom ice” phenomenon, where ice forms on tree stumps, has appeared at Lake Nukabira in this northern Japan town.
The lake in Kamishihoro, Hokkaido, was formed by a dam. When the water level drops due to water releases for power generation, the frozen lake surface is pushed up onto the submerged stumps, creating shapes that resemble mushrooms.
“Ice bubbles” are seen on the surface of Lake Nukabira in Kamishihoro, Hokkaido, on Jan. 13, 2026. (Mainichi/Daiki Takikawa)
The phenomenon is a seasonal attraction in the region, with some formations reaching about 1 meter high. Visitors can walk across the surface of the frozen lake. On days without snow, they can also see “ice bubbles” — gas bubbles rising from the lake bottom and becoming trapped within the ice.
According to the local tourism association, these unique sights can typically be enjoyed from January through early March.
(Japanese original by Daiki Takikawa, Photo and Video Department)
AloJapan.com