How Do You Stay Safe in Kusatsu? The Volcano, Volcanic Gas and Bears

Published 2026-10-04 · Sources checked 2026-10-04 · Treasure Hunting Co., Ltd.

This guide is for visitors to Kusatsu Onsen who plan to drive or hike in the hills above the town. It covers the Kusatsu-Shirane volcano, the road over the mountain, volcanic gas, bears and what to do in an emergency.

We used pages from the Japan Meteorological Agency (JMA), Kusatsu Town, the Kusatsu Onsen Tourism Association and the Fire and Disaster Management Agency, all read on 2026-10-04. Conditions on a volcano can change quickly, so check the current JMA status and local notices on the day.

The short answer: a quiet volcano, with limits near the crater

Kusatsu-Shirane is an active volcano above the town. On 15 May 2026 at 11:00, JMA lifted its eruption warning for the area around Yugama crater. It lowered the eruption alert level from Level 2 (crater area restrictions) to Level 1, which JMA words as "be aware this is an active volcano".

JMA said the chance of an eruption affecting the area within about one kilometre of Yugama crater had become low. It said the volcano was returning to its quiet state.

What JMA still warns about

Level 1 does not mean there is no danger. The same JMA notice gives two cautions:

• Within about 500 metres of Yugama crater, a very small release of ash is possible. JMA asks people to follow the instructions of local authorities and stay out of dangerous areas.
• Volcanic gas comes out around Yugama crater. In hollows and valleys nearby, a high concentration of gas can collect.

JMA's own explanation of alert levels adds that levels do not always move one step at a time. An eruption can happen without any warning signs. It also says rain can cause mud flows, which an eruption warning does not cover.

What is closed near the crater

The Kusatsu Onsen Tourism Association published a notice about Route 292, the Shiga-Kusatsu road. It says the road reopened to through traffic at 13:00 on 29 May 2026. The notice says this could change with the weather.

The same notice says Kusatsu Town set a restricted zone within a 500-metre radius of the crater under the Disaster Countermeasures Basic Act. As a result:

• You cannot visit Yugama crater.
• For the time being, the town asks people to avoid the hiking trails that lead into the restricted zone from outside it.
• The Shirane Rest House and the summit car park were not yet open. The notice says it would take time to prepare them.
• For now, the road is open to passing traffic only.

The notice also says that if the alert level rises again, regulations will be put in place under an evacuation plan agreed by the local volcano council.

These notices are dated May 2026. We did not find a later notice, so check the town and tourism association pages before you set out.

Strong acid in the spring water

The town office says the main spring water type is strongly acidic, with a pH around 2.0. It says a five-sun nail left in the Yukawa stream dissolves in about ten days. That is a reason to take care with the water, but we did not find official bathing advice, so we have none to give.

Bears

Kusatsu Town warns that bears have been seen in many places, including built-up areas. Its advice includes:

• When you walk on trails or in woods, carry a bear bell or play a radio.
• If you see a bear, do not go near it or provoke it. Move to a safe place.
• Do not leave food near houses, and lock buildings.

The town's page lists sightings from June and July 2026. They include one near the Sessho Kawara viewing point and one at the entrance on Route 292.

In an emergency

The Fire and Disaster Management Agency says to call 119 when you need an ambulance. It says anyone in Japan can use the ambulance service. We could not confirm from official pages whether operators answer in English.

What we could not verify, and therefore left out

• The alert level and road status after the dates of the notices we read. The tourism association's road information page and JMA's current page show the latest.
• Whether the Shirane Rest House, the summit car park and the trails have reopened since 29 May.
• Gas levels at any one place, and any official advice on gas for hikers.
• Emergency numbers other than 119, and whether 110 and 119 operators speak English.

Related guides

• How do you get to Kusatsu Onsen from Tokyo?
• What is Kusatsu Onsen? The Yubatake and the strongly acidic water

Sources

All URLs retrieved 2026-10-04.

1. 噴火予報：警報解除（草津白根山（白根山（湯釜付近））） (Japan Meteorological Agency) — (warning lifted 15 May 2026; Level 2 to Level 1; 500 m and gas cautions)
2. 火山に関する情報の発表状況（草津白根山（湯釜付近）） (Japan Meteorological Agency) — (history of warnings and forecasts; 15 May 2026 entry)
3. 噴火警戒レベルの説明 (Japan Meteorological Agency) — (levels do not always change in order; mud flows are outside warnings)
4. 国道２９２号志賀草津道路の再開通と草津白根山の立入等禁止措置について (Kusatsu Onsen Tourism Association) — (road reopened 29 May 2026; 500 m restricted zone; Yugama, trails, rest house and car park)
5. 草津白根山の噴火警戒レベルの変更に伴う規制について (Kusatsu Town) — (town notice of 15 May 2026 on the level change and the road)
6. 草津温泉について (Kusatsu Town) — (strongly acidic water, pH about 2.0)
7. クマの出没に注意してください (Kusatsu Town) — (bear advice; sightings in June and July 2026)
8. Guide for Ambulance Services (Fire and Disaster Management Agency) — (call 119 for an ambulance; anyone in Japan can use it)