PHIVOLCS issues lahar warning for Mayon Volcano amid Ada

Lahar flows may occur around Mayon Volcano in Albay as Tropical Storm Ada is expected to bring heavy to intense rainfall over parts of Southern Luzon, the Philippine Institute of Volcanology and Seismology (PHIVOLCS) said Friday.

In an advisory, PHIVOLCS said rainfall from Ada could trigger volcanic sediment flows or lahars, muddy streamflow, and muddy runoff along rivers and drainage systems around the volcano.

“Heavy to intense rainfall may generate syn-eruption lahars on major channels draining the southern to eastern slopes of Mayon Volcano by incorporating loose material from new pyroclastic density current (PDC) deposits of its ongoing eruption,” PHIVOLCS said.

These erodible PDC deposits occupy the Mi-isi, Bonga, and Basud Gullies and will likely feed generally in-channel but hot lahars in the Mi-isi and Binaan Channels in the following areas:

• Daraga town
• Barangays Mabinit, Bonga, Matanag, Buyuan and Padang in Legazpi City
• Barangays Lidong and Basud Rivers in Sto. Domingo town

“Hot lahars could cause scalding upon contact that could lead to serious and life-threatening injuries,” PAGASA warned.

Older and erodible eruption deposits on the watershed areas of the southwestern slopes of the volcano can be remobilized as non-eruption lahars in the following areas:

• The Masarawag, Maninila and related distributary channels in Guinobatan town

Mayon lahars can threaten communities downstream of all the above channels with inundation, impacting force (when carrying boulders), buria, and wash out (even to sea off the eastern slopes), PHIVOLCS said.

PHIVOLCS strongly advised the communities and local government units of the concerned areas to keep monitoring the weather and take pre-emptive response measures for their safety from Ada. —VAL, GMA Integrated News