LEGAZPI CITY, Albay – The Philippine Institute of Volcanology and Seismology (Phivolcs) issued a lahar advisory on Monday afternoon, Nov. 24, warning communities around Mayon Volcano to brace for possible volcanic sediment flows due to expected heavy rains from tropical cyclone ‘Verbana.’

The advisory released around 2:30 p.m. came following the Philippine Atmospheric, Geophysical, and Astronomical Services Administration (PAGASA) Southern Luzon heavy rainfall warning issued at 2 p.m. that forecast intense rains over the region from Verbena and the shear line.

Phivolcs cautioned residents and local government units in Albay to closely monitor rainfall conditions and prepare pre-emptive measures, including possible evacuations, to ensure community safety.

According to the agency, the incoming intense to torrential rainfall could mobilize loose volcanic materials from Mayon’s slopes, generating life-threatening post-eruption lahars.

These hazardous mudflows may occur on major rivers and drainage channels that drain the volcano, especially where large deposits remain from the 2018 and 2023 eruptions.

Among identified channels of Phivolcs, particularly at risk, are Miisi and Binaan in Daraga town; Mabinit, Matanag, Bonga, and Buyuan in Legazpi City; Anoling in Camalig, and Basud in Santo Domingo town.

Phivolcs said communities downstream of these waterways could face severe threats such as river inundation, burial from debris, and forceful lahar impact.

The advisory also highlighted potential lahar activity affecting Guinobatan due to older pyroclastic materials on Mayon’s southwestern slopes.

These deposits, historically loosened during heavy rains, may again be washed down through the Masarawag and Maninila channels, posing additional hazards even without a volcanic eruption.

Phivolcs warned that Mayon lahars are powerful enough to transport massive amounts of gravel and boulders and have a long record of damaging properties, reshaping river channels, and washing out to sea.

The agency strongly advised at-risk communities and local government units to maintain heightened alertness and take proactive safety actions as weather conditions worsen.

“Continual monitoring and readiness are essential to prevent loss of life,” they said.

Authorities remain on standby as rains associated with Verbena continue to threaten the region.

Joy Maravillas, chief of the Municipal Disaster Risk Reduction and Management Office (MDRRMO) Guinobatan, said that they have conducted a Pre-Disaster Risk Assessment (PDRA) meeting following the advisory.