The Philippine Institute of Volcanology and Seismology (Phivolcs) warned of possible lahars and sediment-laden streamflows at Kanlaon Volcano as Tropical Depression Basyang (Penha) is expected to bring heavy to intense rainfall to Negros Island and the rest of the Visayas.

In a lahar advisory issued at 10:30 a.m. on Friday, Feb. 6, Phivolcs said prolonged heavy to intense rainfall could generate life-threatening volcanic sediment flows along major channels draining the southern, western and eastern slopes of Kanlaon, which is currently under Alert Level 2 (increased unrest).

It explained that intense rains may erode loose materials from remnant pyroclastic density current deposits from the Oct. 24, 2025 explosive eruption, as well as ashfall from that event and from more recent ash emissions, triggering post-eruption lahars.

It added that non-eruption lahars are also possible in areas on the upper slopes that were recently exposed by landslides or weakened during the passage of Supertyphoon Tino last November, which may trigger debris to be carried into rivers that have previously delivered destructive flows to downstream communities.

Phivolcs said communities in Bago City, La Carlota City, La Castellana, Moises Padilla and San Carlos City in Negros Occidental, as well as Canlaon City in Negros Oriental, may be affected by lahars, sediment-laden streamflows, flooding and siltation, particularly those located along the following channels: 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.

Residents in these areas, as well as those further downstream, were advised to be prepared in case evacuation becomes necessary and to avoid crossing affected streams, even those farther downslope of the volcano.

Phivolcs added that Kanlaon lahars, which were shown during Supertyphoon Tino are capable of transporting large volumes of gravel and boulders, which could threaten communities through strong impact, inundation, burial and washout.