Mount Semeru Erupts Again: Hot Clouds Travel 5.5 KM as Indonesia’s Most Active Volcano Shows Increased Activity
Mount Semeru, the tallest volcano on the island of Java and one of Indonesia’s most iconic natural landmarks, erupted again today, sending hot clouds racing 5.5 kilometers down its southeastern slope.
The eruption, recorded on Wednesday (November 19, 2025) at 04.00 Pm, marks yet another episode in what has been an exceptionally active year for Semeru.
According to reports from local monitoring posts, a dense, dark-gray ash column rose powerfully from the summit crater, drifting toward the north and northwest.
The Mount Semeru Observation Post recorded the eruption with a maximum amplitude of 40 mm and a duration of 16 minutes and 40 seconds, indicating a significant explosive event.
At the time of reporting, volcanic activity was still ongoing.
5.5 KM Hot Cloud Reaches Besuk Kobokan
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The pyroclastic surge, commonly referred to as a hot cloud, stretched 5.5 km from the crater toward the Besuk Kobokan valley, an area that has repeatedly been struck during Semeru’s previous eruptions.
These hot clouds pose extreme danger due to their speed and temperatures that can exceed hundreds of degrees Celsius.
Authorities Urge Tourists and Hikers to Stay Clear
Mukdas Sofian, an officer at the Mount Semeru Monitoring Post, issued a strong warning to residents, hikers, and tourists:
- No activities are allowed within 8 km of the southeast sector, particularly along Besuk Kobokan.
- Beyond that distance, people must stay at least 500 meters away from riverbanks due to the potential spread of hot clouds and lava flows that can reach up to 13 km from the summit.
- A 2.5 km exclusion zone around the summit is strictly enforced because of the risk of flying incandescent rocks.
He also advised the public to stay alert for lava falls, lahars (volcanic mudflows), and additional hot clouds that may follow the initial eruption.
Rivers and valleys connected to the summit, such as Besuk Kobokan, Besuk Bang, Besuk Kembar, and Besuk Sat, are particularly vulnerable.
Semeru: Indonesia’s Most Active Volcano in 2025
Throughout 2025, Mount Semeru has recorded a staggering 2,802 eruptions, making it the most active volcano in Indonesia this year.
Despite its intense activity, Semeru remains at Alert Level II (Warning), meaning eruptions may occur at any time and the public should remain vigilant.
What This Means for Travelers and Volcano Enthusiasts
Mount Semeru is one of the most popular destinations for trekkers exploring East Java, especially those seeking sunrise views from the slopes or wishing to explore nearby attractions like Tumpak Sewu Waterfall and Mount Bromo.
Also Read BROMO IJEN TUMPAK SEWU TOUR 4 DAYS 3 NIGHTS
However, with ongoing eruptions and unpredictable volcanic activity, travelers are strongly advised to postpone hikes to Semeru, monitor official updates, and prioritize safety.
While East Java remains open to tourism, authorities recommend focusing on safer locations such as Mount Bromo, Ijen Crater, or the surrounding nature parks until conditions stabilize.
Adventure seekers and nature lovers should follow updates from official sources and avoid restricted zones at all costs.
Volcanic landscapes are stunning, but respecting safety guidelines ensures that everyone can enjoy Indonesia’s natural wonders responsibly.
Source:
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https://bpbd.lumajangkab.go.id/
