“Yugama” (Crater Lake) is located on Mt. Kusatsu-Shirane, which has a mysterious atmosphere with vibrant emerald green lakes on white rocky surfaces where plants do not grow. Let’s enjoy another world created by a volcano with an altitude of 2000 meters.
About 30 minutes by car from Kusatsu Onsen town. Yumaga is located in Mt. Kusatsu-Shirane, northwest of Gunma Prefecture. Kusatsu Shirane is an active volcano with an altitude of 2160 meters. At the top of the mountain, you can see the sci-fi sight created by Yugama, a desolate land like the Moon World and an emerald green lake.
An eruption that sometimes rages on people’s lives. Mt. Kusatsu-Shirane has repeatedly erupted many times in the past. A little while ago you could walk to the edge of the Yugama crater. However, since 2010, the area of access has expanded due to the effects of volcanic activity. From 2014 to June 2017, the eruption warning level increased and Yugama and its surroundings were banned.
Yugama is one of the most acidic lakes in the world. The volcanic gas that springs from the bottom of the lake melts into the water and turns into sulfur, creating a fantastic color of emerald green. Therefore, it does not freeze even in the extremely cold winter. The acidity is so high that it will melt just by immersing the nail for a day. Of course, entry to the lake is prohibited. You can enjoy the beautiful scenery slowly from the nearby observation deck.
Here is how to access. The time required from the center of Tokyo is about three and a half hours. If you are going by car, take the Kanetsu Expressway “Shibukawa Ikaho IC” to Route 145 and Route 292 (Shiga Kusatsu Road) to “Shirane Mountain Rest House”. In the case of public transportation, take a bus bound for Shirane Volcano (JR Bus Kanto) from Japan Railway Naganohara Kusatsuguchi Station or Kusatsu Onsen Bus Terminal. There is “Shirane rest house” in front of the arrival bus terminal.
First, let’s aim for “Kusatsu Shirane Rest House”, which will be the gateway to Yumaga. Kusatsu Shirane Rest House is located at an altitude of 2000 meters and has a large parking lot. Stop here and head to the observatory where you can get a panoramic view of Yugama while enjoying a short hike. Please note that the Shiga Kusatsu Road is closed during the winter season from early November to mid-April.
The summit is a wide observation space, and you can see Yugama in the distance. A lake that shines like a jewel can be seen in the back of the earth where no vegetation grows as if it fell on the moon. The surface of the lake becomes milky white when the sun comes into, and becomes cobalt blue when the sun goes down. Precious scenery that can only be seen for about half a year from May to November other than closing in winter spreads in front of you.
Speaking of Kusatsu in Gumma Prefecture, Kusatsu hot springs are also famous in Japan, and not only in Japan, but also from abroad. However, surrounding Kusatsu is actually a treasure trove of not only hot springs but also superb views. “Yugama” (Boiler) of Mt. Kusatsu-Shirane is the crater-lake of the emerald green seen at the summit of the active volcano near the prefectural border of Gunma prefecture and Nagano prefecture. And the beautiful emerald green water shine which is the biggest feature of Yugama is believed to be produced by absorbing light of a specific wavelength, such as iron ions and sulfur dissolved in water.
Because Mt. Kusatsu-Shirane with Yugama is an active volcano, we can not tour sight of Yugama depending on volcanic alert level. Since there are frequent cases where restrictions on entry into the mountain are applied to this area, it is a sightseeing spot that you would like to visit if you have a chance.
Because the altitude of Yugama is also a mountainous area with more than 2000 meters, the weather is easy to change, even if the Kusatsu hot spring is cloudy, the summit is sunny and vice versa. Also, as toxic gases are generated, it is dangerous, so there is an area where it is prohibited to enter the area, it will be a tour from the observatory without getting down to the lake.
Because Yugama is located about 30 minutes by car from Kusatsu hot spring town, it is a spot where you can easily feel sightseeing. Especially, in the autumn leaves time period, you can watch the mountains stained red from the observatory in the daytime and enjoy the drive while watching the lighted-up autumn leaves in the evening. Yugama is also known as sacred place from its mysterious shade. Autumn is a recommended season when you can enjoy autumn leaves on your way home after seeing the lake of emerald green.
Since the parking lot is on the Shiga Kusatsu Road, you can not visit Yugama during the winter season. You can only visit during late April to mid November.
“Yugama” is the popular tourist attraction in Kusatsu highlands, and one of the crater-lakes which was made by the eruption of the volcano Shirane (2,160 meters high). Its diameter is 300 meters, depth of water is 30 centimeters, water temperature is around 18 degrees, and calmly filled with the beautiful emerald green water.
It is said that it is the strongest acidic lake (PH1.20) in the world and fish cannot live in such extreme acidity water. In addition, because of a lot of volcanic ashes, viscosity is strong and the quality of the water is very thick. Of course you cannot swim in here. If you enter inside of it, you gradually oxidized and begin to dissolve without being able to move.
However, the contrast of the white face of the mountain keeping out the plants and the surface of the emerald green produce mysterious atmosphere.
But, as of September, 2016, “the Yugama visit course” is forbidden to come in by raising Mt. Shirane’s volcanic alert level.
Under the eruption of Mt. Kusatsu-Shirane on 23rd January 2018, it is restricted to mountain again. Visitors are not allowed to enter the area within a 1km radius, centering on the Yukama.
|Adresse:||Kusatsu-Shiranesan Kusatsu-cho Agatsuma-gun, Gunma 377-1711 Japan|
|Access:||JR Agatsuma-sen line "Naganohara Kusatsuguchi-eki Station” (Approximately 1 hour by bus)|
|Tel:||(+81)279-88-0800 (Kusatsu Hot Springs Tourism Association)|