By CESAR JOLITO III
State volcanologists warned communities around Kanlaon Volcano to be on heightened alert as Tropical Storm “Ada” is expected to bring rains that could trigger dangerous lahar flows and sediment-laden flooding in parts of Negros Island.
In a lahar advisory issued yesterday, the Philippine Institute of Volcanology and Seismology (Phivolcs) cited the state weather bureau’s heavy rainfall warning released earlier, which forecast light to moderate rains with occasional heavy downpours across Negros Island and the Visayas.
Phivolcs said the anticipated rainfall could generate volcanic sediment flows, muddy runoff and siltation along rivers and drainage systems surrounding Kanlaon, which remains under Alert Level 2.
According to the agency, prolonged heavy rains may produce life-threatening lahars and sediment-laden streamflows along major channels draining the southern, western and eastern slopes of the volcano.
These may result from the erosion of loose volcanic materials left by recent ash emission events and remnants of pyroclastic density current deposits from past explosive activity.
Phivolcs also warned that non-eruption-related lahars are possible, particularly in areas weakened by landslides or damaged during the onslaught of Typhoon “Tino” in November 2025.
These conditions could feed debris into rivers that have previously caused destructive flooding in downstream communities.
Areas identified as potentially affected include Bago City, La Carlota City, La Castellana, Moises Padilla, and San Carlos City in Negros Occidental, as well as Canlaon City in Negros Oriental.
Rivers and waterways under close watch include the Ibid, Cotcot, Talaptapan, Malaiba, Panubigan, Buhangin-Indurayan, Najalin, Inyawan, Maragandang, Panun-an, Intiguiwan, Camansi, Maao, Tokon-tokon, Masulog, Binalbagan, Taco Creek, and Linothangan Rivers.
Phivolcs advised residents living along these channels and in downstream areas to remain vigilant, prepare for possible evacuation, and avoid crossing rivers and streams during periods of heavy rainfall, even in areas farther from the volcano.
The agency emphasized that past lahars at Kanlaon, particularly during “Tino,” were powerful enough to carry large volumes of gravel and boulders, posing serious risks of impact, inundation, burial, and washout to nearby communities./CJ, WDJ