New glaciers found in the Japan Alps

A survey by Niigata University and others has confirmed that two more snowfields in the region around Shirouma (2,932m) qualify as "glaciers." The new ice streams bring the total of relic glaciers discovered in the Northern Japan Alps to seven or so – joining the three discovered on Tsurugi and Tateyama in 2012 and two more subsequently found on or around Shirouma.

NHK Shinshu announces the discovery of the new glaciers.

The two newly confirmed glaciers are located under the Kaerazu-zawa and Shakushi-zawa snowfields. The latter can be seen from Hakuba Village at the foot of the Shirouma (“White Horse”) massif. Shirouma is one of Fukada Kyūya’s One Hundred Mountains of Japan.

The view from Hakuba Village.

A snowfield, says NHK (see references below), is defined as a localised area of snow that remains even in the summer. It qualifies as a glacier when it meets certain criteria, such as the ice masses within it moving at a certain speed.

In a survey conducted by Niigata University and others from 2021 to 2022, it was confirmed that an ice mass with a maximum thickness of 43 meters in the Shakushi-zawa snowfield moved up to 26 centimetres in about one month, and an ice mass with a maximum thickness of 29 meters in the Kaerazu-zawa snowfield moved up to 14 centimetres. A paper summarising the survey results will be published in an international scientific journal.

Locations of the Karamatsu-zawa and Kaerazu-sawa snowfields.

There are now four snowfields in Nagano Prefecture that have been confirmed to be glaciers, including the Kakunesato snowfield on Kashimayari (2,889m), another of Fukada’s One Hundred Mountains, and the Karamatsu-zawa snowfield above Hakuba Village.

Researchers on one of the Shirouma snowfields.

As quoted by NHK, Professor Narama Chiyuki of Niigata University, who conducted the survey, said "The impact of global warming on the Japanese Alps has not been fully understood due to a lack of long-term observation data. We believe that the newly discovered glaciers can be used as an indicator of environmental change, and we would like to continue observing them in the future."

References

NHK Shinshū news web, 白馬村の２つの雪渓 新たに「氷河」と確認 新潟大などの調査, 20 January 2025.

Yama to Keikoku magazine, 北ア白馬の２雪渓新たに’氷河’と確認, March 2025 edition.