Mt. Shirane is the name for a series of volcanic mountains located in Kusatsu-machi, Agatsuma-gun in Gunma Prefecture (2.171 m). The volcanic peaks are Mt. Shirane, Moto-Shirane, and Aino-mine. The famous sight-seeing spots, Mt. Shirane and Moto-Shirane can be enjoyed in all four seasons, attracting many tourists every year.
The peaks of Mt. Kusatsu-Shirane used to be covered with trees and alpine plants, but due to the eruption that occurred in 1882, the surface of the mountain has since become infertile. This degraded land's surface looks white which is considered one of the unique characteristics of Mt. Kusatsu-Shirane.
Mt. Kusatsu-Shirane's volcanic activity started 57, 0000 years ago. There are several craters on the top of Mt. Kusatsu-Shirane, a result from an eruption in the past. The three famous hot water craters are called Yugama, Mizugama and Kogama created by a recent hydration explosion. Other famous ones are called Yumi-ike and Kagami-ike, and also contain water.
When reaching the rest house at the peak of Mt. Kusatsu-Shirane, you will see a path to Yugama, a hot water crater consisting of acidic turquoise-colored water with rafts of yellow sulfur floating on its surface. The contrast made by the crater's beautiful blue and the mountain's bare surface is definitely a must-see.
At a pH of 1, Yugama is considered the most acidic lake in the world. The dimensions of Yugama are an area of 52,600 m2, with a diameter of 300m and a depth of 30m. There are no plants or trees around Yugama and it is surrounded by brown walls made by the eruption. The view is absolutely spectacular, but there is a strong smell of sulfur.
*When Shiga-Kusatsu road (route 292) is blocked for winter, people are NOT allowed to visit this crater.
There is a ropeway from the middle of Mt. Shirane to Ainomine which takes hikers to the main hiking course of Mt. Moto-Shirane. While hiking, people enjoy the view of the Komakusa plants, the famous alpine plants in Kusatsu.
The best time to go see the autumn leaves is from the end of September to the middle of October. From the parking lot of Sanrei Station at Mt. Shirane (Free in summer time), it takes about 5 minutes on foot to a famous spot for autumn leaves.
Mt. Shirane will be covered with powdery snow in the winter which is perfect for skiing. Kusatsu International Ski Resort opens from early December to the middle of April which is relatively longer than other ski resorts. The resort is a full-sized facility featuring eight kilometers of downhill course. After enjoying skiing, tourists love to stop by Kusatsu Hot Spring Resort to get rid of their fatigue. Kusatsu International Ski Resort is constantly improving their facility with new features such as the Baelz Onsen Center, an open-air hot spring and a slope open only for snow boarders (snowboarding has become very popular recently). The facility also features limited space for children called "Kid's Square", making it a more family-oriented facility.
Shuttle Information: There is a free shuttle running during the ski season.
The bus runs around Kusatsu Onsen Bus Terminal – Kusatsu International Ski Resort (Mt. Tengu) – Shirane Volcanic Mountain Ropeway Sanrei Station/