The Philippine Institute of Volcanology and Seismology (Phivolcs) issued a strong warning on Monday for residents near Mayon Volcano, advising them to prepare for potential life-threatening volcanic mudflows, or lahars, as heavy rainfall is forecast for the Bicol Region.
The warning comes as the region faces intense rains triggered by the combined effects of Tropical Depression Verbena and a shear line.
Phivolcs specified that this torrential downpour could generate powerful lahars by eroding the substantial loose pyroclastic material left behind by Mayon’s 2018 and 2023 eruptions.
According to the advisory, muddy streamflows and run-off are highly probable in river and drainage areas.
The agency is urging local government units and communities to prioritize increased vigilance, readiness, and if necessary, immediate pre-emptive evacuation in zones previously identified as high-risk for lahar and related hazards in Albay province.
Communities downstream of major channels—including Miisi, Binaan, Mabinit, Buyuan, Anoling, Matanag, Bonga, and Basud—are under severe threat from these post-eruption flows.
The town of Guinobatan also faces a separate danger from non-eruption lahars fed by older pyroclastic deposits on the volcano’s southwestern slopes.
Phivolcs emphasized that Mayon’s lahars are historically powerful, capable of carrying massive volumes of gravel and boulders, posing a threat through sheer force, inundation, and burial.
Local authorities are advised to continuously monitor rainfall and implement safety measures without delay.