The Philippine Institute of Volcanology and Seismology (PHIVOLCS) has warned communities in Albay of possible lahar flows at Mayon Volcano due to heavy rainfall expected from Tropical Storm Ada.
In a lahar advisory issued on Friday, PHIVOLCS said intense to heavy rains brought by the storm could trigger lahar flows and river flooding around the volcano, with rainfall estimates ranging from 100 to 200 millimeters.
“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.
According to the agency, erodible PDC deposits are present in the following areas:
- Daraga: Mi-isi, Bonga, and Basud
- Legaspi City: Mabinit, Bonga, Matanag, Buyuan, and Padang
- Sto. Domingo: Lidong and Basud rivers
PHIVOLCS warned that "hot lahars could cause scalding upon contact, potentially leading to serious and life-threatening injuries."
The agency also noted that older, erodible eruption deposits on the watershed areas of the volcano’s southwestern slopes could be remobilized as non-eruption lahars. These may affect the floowing areas:
- Guinobatan: Masarawag, Maninila
"Mayon lahars can threaten communities downstream of all the above channels with inundation, impacting force (when carrying boulders), burial and wash out (even to sea off the eastern slopes)," said PHIVOLCS.
The bureau strongly advised local government units and residents in high-risk areas to closely monitor weather updates and take pre-emptive measures to ensure their safety as Ada approaches.
PHIVOLCS also confirmed that Mayon Volcano remains under Alert Level 3, indicating magmatic unrest and the possibility of hazardous eruptions.
Meanwhile, the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) reported that Signal No. 1 has been raised in several parts of the country as Ada continues to move slowly north-northwestward over the Philippine Sea east of Eastern Visayas.
