Semeru Erupts, Hundreds of Climbers Remain at Ranu Kumbolo

MALANG, KOMPAS – Hundreds of climbers are taking shelter at Ranu Kumbolo during the eruption of Mount Semeru. Their condition is safe, and they are scheduled to descend on Thursday (20/11/2025).

When Semeru erupted on Wednesday (19/11/2025), there were approximately 187 individuals consisting of climbers, porters, guides, and officials who were at Ranu Kumbolo at that time. Since the beginning of the year, based on recommendations from the Center for Volcanology and Geological Disaster Mitigation (PVMBG), climbing Semeru has indeed been limited to Ranu Kumbolo.

Ranu Kumbolo is a lake located along the Semeru hiking trail, at an altitude of 2,390 meters above sea level. This 12-hectare lake has become one of the favorite resting points for climbers.

"Based on the recommendations from PVMBG, considering the increased status of Semeru, we are closing climbing activities up to Ranu Kumbolo until conditions are declared safe. Currently, there are 187 individuals at Kumbolo, including climbers, porters, guides, and officials, and they are in a safe condition," said the Head of the Bromo Tengger Semeru National Park Authority (BB TNBTS) Rudijanta Tjahja Nugraha, Thursday (20/11/2025).

According to Rudijanta, the eruption material is moving towards the South and Southeast. Meanwhile, the position of Ranu Kumbolo is located to the North of Semeru, thus it is not directly affected by the eruption.

"Considering the weather yesterday afternoon with rain and the conditions starting to darken, it was decided that the climbers would descend today accompanied by officers and guides who will escort and ensure that all climbers arrive at the starting point of the Ranupani ascent later this afternoon," said Rudijanta.

For visitors who have already booked climbing tickets to Ranu Kumbolo, according to Rudijanta, they will be rescheduled. "Meanwhile, tourism towards Bromo and Ranu Regulo remains open as usual. We urge the public to comply with and adhere to the danger zones established by PVMBG," he said.

For your information, climbing Mount Semeru requires traversing several routes. The starting point of the ascent begins at Ranupani-Ranu Regulo, followed by Waturejeng (located 5 km from Ranupani), Ranu Kumbolo (a lake approximately 6.5 km from the summit of Semeru), Oro-oro Ombo (a yellowing grassland covering about 100 hectares with views of cliffs and hills), the small Panggonan grassland (located in the Ayek-Ayek hill area), Cemoro Kandang forest (situated to the west of Oro-oro Ombo), Hourbangan grassland (at an altitude of 3200 meters above sea level), Kalimati (where the vegetation consists of grassland and edelweiss over an area of approximately 20 hectares), Arcopodo (a steep and sloping path where landslides frequently occur, with many graves of climbers found here), Cemoro Tunggal (at this location, there is only one type of vegetation, a pine tree, which is usually used as a marker by climbers), and the summit of Mahameru.

Currently, out of the approximately 300 registered refugees, most leave the evacuation site during the day. They return to save their belongings.

"If during the day the refugees return home, the ongoing activity is the communal kitchen," said Taruna Siaga Bencana (Tagana) officer from Lumajang, Rudy Moch Kholiq.

According to Rudy, so far, residents affected by the Semeru eruption in 2021 have mostly returned to their original homes. They occupy the permanent housing (huntap), which was built by the government, only on weekends. This is because the location of the huntap in Sumber Mujur Village, Candipuro, is considered far from agricultural areas or the daily activities of the residents.

"However, with their homes severely damaged in this eruption, it is highly likely that they will fully occupy the temporary shelters," said Rudi.

As of Thursday afternoon, the activity of Semeru has been relatively stable. During the observation from 00:00 to 06:00 WIB, Semeru erupted 25 times, recorded 32 collapse earthquakes, experienced 1 puff, and 1 distant tectonic earthquake.

"The status of Semeru remains Alert. The public is urged to adhere to the recommendations of PVMBG, which advise against any activities in the southeastern sector along Besuk Kobokan, within a distance of 20 km from the summit (the eruption center). Beyond this distance, the public should refrain from activities within 500 meters from the riverbank (river buffer) along Besuk Kobokan due to the potential risk of being affected by the expansion of hot clouds and lahar flows," said Hadi Wijaya, Head of the Center for Volcanology and Geological Disaster Mitigation (PVMBG).

The community, according to Hadi, is also advised not to engage in activities within an 8 Kilometer (Km) radius from the crater/summit of Semeru due to the risk of volcanic rock ejections (pyroclastic). "It is essential to remain vigilant of the potential for hot clouds, lava flows, and lahars along the river valleys that originate from the summit of Semeru Volcano, particularly along Besuk Kobokan, Besuk Bang, Besuk Kembar, and Besuk Sat, as well as the potential for lahars in the small rivers that are tributaries of Besuk Kobokan," he stated.