PHIVOLCS warns of possible lahars at Kanlaon volcano as heavy rain from Severe Tropical Storm Kalmaegi approaches
The Philippine Institute of Volcanology and Seismology (PHIVOLCS) has issued a lahar advisory for Kanlaon volcano on Negros Island, warning that heavy to intense rainfall from Severe Tropical Storm Kalmaegi, known locally as Tino, may generate volcanic sediment flows on the volcano’s southern and western slopes.
Minor explosive eruption at the summit crater of Kanlaon volcano on October 24, 2025. Credit: PHIVOLCS
PHIVOLCS released the Kanlaon volcano Lahar Advisory at 11:30 local time (LT) on November 3, citing data from PAGASA Tropical Cyclone Bulletin No. 6, issued the same morning at 11:00 LT. PAGASA forecasts heavy to intense rainfall over parts of Central Philippines, including Negros Island, as Severe Tropical Storm Kalmaegi (Tino) moves across the Visayas region.
According to PHIVOLCS, such rainfall could erode loose volcanic material deposited by the October 24 explosive eruption, a short three- to four-minute event that generated pyroclastic density currents descending the volcano’s southern slopes.
Additional loose ash from more recent minor ash emissions also increases the likelihood of sediment mobilization during prolonged or intense rain.
The agency warned that prolonged and heavy rainfall may generate channel-confined post-eruption lahars and sediment-laden streamflows on major drainages descending the southern and western slopes.
Tamburong / Ibid Creek in Barangay Biak-na-Bato and Baji-Baji Falls and Talaptapan Creek are identified as the most susceptible to lahars.
These drainages overlie recent pyroclastic density current deposits and may channel potentially hot lahars or dense, muddy streamflows. Flows could extend further downslope along connected rivers and tributaries.
PHIVOLCS urged residents and local authorities to remain vigilant, avoid traversing affected streams, and prepare for evacuation if rainfall intensifies. Communities located along or downstream of the identified channels were reminded that flows may reach areas farther from the volcano and that conditions can change rapidly.
Kanlaon Volcano remains under Alert Level 2 (moderate unrest). The agency is maintaining 24-hour volcanic and seismic monitoring.
References:
1 KANLAON VOLCANO LAHAR ADVISORY – PHIVOLCS – November 3, 2025
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