The Philippine Institute of Volcanology and Seismology (Phivolcs) issued separate lahar advisories on Monday for communities near Mayon Volcano in Albay and Kanlaon Volcano in Negros Island as Tropical Cyclone Verbena and the shear line bring rains in the coming days.

In its 2:30 p.m. advisory, Phivolcs said intense rains over the Bicol Region may result in volcanic sediment flows, lahars, and muddy streamflows across the major drainage channels of Mayon Volcano.

It added that heavy rainfall may generate “life-threatening post-eruption lahar” by eroding loose material from deposits of the 2018 and 2023 Mayon eruptions.

Communities along Miisi, Binaan, Mabinit, Buyuan, Anoling, Matanag, Bonga, and Basud Channels are warned of severe lahar threats, while areas in Guinobatan may be affected by previously weakened southwest slopes that may generate non-eruption lahars.

Meanwhile, similar warnings were raised for Kanlaon Volcano, which is currently at Alert Level 2. Potential lahars, sediment flows, and muddy runoff in rivers and channels surrounding the volcano may be expected.

Areas that may be affected include Ibid, Cotcot, Malabia, Talaptapan, Panubigan, Buhangin-Indurayan, Najalin, Inayawan, Maragodang, Panan-an, Intiguiwan, Camaasi, Maoa, Tokton-Tokon, Masulog, Binalbagan, Taco, and Linothangan Rivers, among others.

Prolonged rainfall may also remobilize pyroclastic density current deposits and older erodible volcanic materials, increasing lahar risks in communities of Bago City, La Carlota City, La Castellana, Moises Padilla, San Carlos City, and parts of Negros Occidental and Negros Oriental.

Phivolcs advised residents and local government units to maintain vigilance, readiness, and consider pre-emptive evacuation if necessary.