Destructive cold lahar at Mount Merapi sweeps away vehicles following heavy rain, Indonesia
Heavy rainfall on March 3, 2026, triggered a destructive volcanic mudflow on Mount Merapi’s Kali Senowo channel in Magelang Regency, Central Java, Indonesia, sweeping away at least three trucks and one car.
Destructive lahar at Mount Merapi on March 3, 2026. Credit: INFOMITIGASI
A rain-triggered cold lahar descended the western slope of Mount Merapi on Tuesday afternoon, March 3, sweeping through the Kali Senowo river corridor and carrying at least three sand-mining trucks and one car downstream.
The flow followed several hours of heavy rain over the upper catchment, re-mobilizing fresh volcanic deposits that had accumulated after weeks of dome collapse and lava-flow activity.
According to a field report by the regional outlet Bidik Ekspres ID, the lahar struck the river stretch between Muntilan and Krinjing in Magelang Regency at approximately 15:00 local time. Eyewitnesses said the impacted trucks were operating in a sand-extraction zone along the channel when the sudden surge arrived, leaving no time for evacuation.
No casualties have been reported so far, but equipment damage was considerable.
Indonesia’s Center for Volcanology and Geological Hazard Mitigation (PVMBG) and its Yogyakarta-based Center for Volcanology and Geological Disaster Mitigation (BPPTKG) issued repeated warnings in late February and early March about the possibility of rain-triggered secondary hazards on Merapi’s flanks.
In its daily bulletin for March 3, the national monitoring network MAGMA Indonesia reported five lava avalanches toward the Kali Krasak river, and maintained the volcano’s alert level at III (“Siaga”).
Two days earlier, BPPTKG official Agus Budi Santoso confirmed a high frequency of lava and hot-cloud avalanches toward the Krasak, Bebeng, and Sat/Putih drainages between February 20 and 26.
Santoso urged the public to remain alert to the potential for lava and hot-ash avalanches, especially when it rains around Merapi. Those river valleys form a connected hydrological network with the Kali Senowo, the site of Tuesday’s lahar.
Satellite and aerial data indicate that Merapi’s south-west dome had recently lost more than 120 000 m3 (4.24 million ft3) of material, supplying large volumes of loose ash, sand, and boulders to down-slope channels. When combined with high-intensity rainfall typical of Java’s late wet season, the materials formed a dense, fast-moving flow capable of transporting vehicles and large rocks for several kilometres.
No evacuation orders have been issued, but local authorities closed river-bank access points and warned residents against entering mining zones until weather conditions improve.
Mount Merapi is among Indonesia’s most active volcanoes, dominating the landscape north of Yogyakarta. Frequent dome-growth and collapse episodes generate pyroclastic flows and lahars that routinely impact cultivated valleys on the western and southern flanks.
The current phase of activity, ongoing since 2020, is characterized by effusive lava emission and periodic rain-triggered mudflows during the monsoon months of January to March.
March falls within Java’s rainy season (November–March), which peaks in January/February, making conditions still highly conducive to rain-triggered lahars as volcanic slopes remain saturated with accumulated wet-season debris.
Updates
15:15 UTC, March 4
The lahar killed at least three people and left two more missing as of the afternoon of March 4, with a joint search and rescue operation still underway.
Three sand-mining trucks were swept away entirely, while twelve more were buried under lahar deposits along with two excavators. A secondary landslide triggered by the event damaged the road connecting Desa Paten and Desa Sewukan in Dusun Bandung.
A joint search and rescue operation was deployed from Tuesday afternoon, led by the Basarnas Borobudur unit and backed by TNI, Polri, K9 dog units from Polresta Magelang, and drones used to map the river corridor. The operation is estimated to continue for up to one week, with searchers combing boulder fields and sand deposits several kilometres downstream.
References:
1 Merapi activity information – MAGMA Indonesia – Accessed March 3, 2026
2 Gunung Marapi erupsi Selasa 3 Maret dini hari, warga diminta waspada banjir lahar – Antara – March 3, 2026
3 Banjir Lahar Dingin Seret Tiga Truk di Magelang Jawa Jawa Tengah – Bidik Ekspres – March 3, 2026
4 Merapi – GVP – Accessed March 3, 2026
I'm a dedicated researcher, journalist, and editor at The Watchers. With over 20 years of experience in the media industry, I specialize in hard science news, focusing on extreme weather, seismic and volcanic activity, space weather, and astronomy, including near-Earth objects and planetary defense strategies. You can reach me at teo /at/ watchers.news.
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