Phivolcs warns of lahar risk from Kanlaon due to storm

By Glazyl M. Jopson

BACOLOD CITY—The Philippine Institute of Volcanology and Seismology has urged heightened vigilance and preparedness among communities near Kanlaon Volcano due to the risk of lahar, or mudflow, triggered by heavy rains from Tropical Storm Ada.

Phivolcs said areas at risk 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.

Communities located along river channels that may be affected by lahars, sediment-laden streamflows, flooding and siltation include Ibid River, Cotcot River, Talaptapan River, Malaiba River, Panubigan Creek, Buhangin–Indurayan River, Najalin River, Inyawan River, Maragandang River, Panun-an Creek, Intiguiwan River, Camansi River, Maao River, Tokon-tokon River, Masulog River, Binalbagan River, Taco Creek and Linothangan River.

Phivolcs advised residents in these areas to prepare for possible evacuation and to avoid crossing affected streams, including those farther downslope from the volcano.

The agency cited a weather advisory from the Philippine Atmospheric, Geophysical and Astronomical Services Administration stating that the storm may bring light to moderate, and at times heavy, rainfall over Negros Island and the rest of the Visayas.

Phivolcs said the rainfall could generate volcanic sediment flows or lahars, sediment-laden streamflows, muddy runoff and related siltation in rivers and drainage areas around Kanlaon Volcano, which remains under Alert Level 2.

In an advisory issued Friday, the agency said prolonged heavy rainfall could trigger life-threatening lahars and sediment-laden streamflows along major channels draining the volcano’s southern, western and eastern slopes.

Post-eruption lahars may also be generated as heavy rains erode loose material from remnant pyroclastic density current deposits of recent explosive eruptions and accumulated ashfall from recent ash emissions.

Non-eruption lahars may occur when upper-slope areas weakened by landslides or exposed during the passage of Super Typhoon Tino in November 2025 collapse and feed debris into rivers that have previously produced destructive flows downstream.

Phivolcs said past typhoons showed that Kanlaon lahars are strong enough to transport large volumes of gravel and boulders, posing threats through impact, inundation, burial and washout.

Local government units in identified risk areas were advised to continuously monitor rainfall conditions and implement preemptive response measures to ensure public safety.

Meanwhile, the Negros Occidental Provincial Disaster Risk Reduction and Management Council Emergency Operations Center has been placed under blue alert status effective immediately due to Tropical Storm Ada.

Under blue alert, emergency response units are on standby with heightened preparedness, while monitoring and coordination with local government units continue.

Provincial response clusters have been activated, including camp coordination and management, food and non-food items, logistics, search, rescue and retrieval, health, law and order, clearing and civil works, and education.

Authorities said the red alert status at the Provincial Disaster Risk Reduction and Management Council Emergency Operations Center will remain in effect for Kanlaon Volcano due to the continuing Alert Level 2, to allow close monitoring and coordination.