Based on Tropical Cyclone Bulletin Number 3 issued by the Philippine Atmospheric Geophysical and Astronomical Services Administration (PAGASA) at 5 a.m. on Wednesday, December 18, 2024, the shear line and Tropical Depression Querubin (and their interaction) will bring potentially heavy to intense rainfall over several areas in southeastern Luzon, Visayas and Mindanao, even those far from the projected path of the tropical depression.
Moderate to heavy rainfall is expected over Bicol Region and Negros Island in the coming days.
“This can generate volcanic sediment flows or lahar, muddy streamflows or muddy run-off in rivers and drainage areas on the monitored active volcano,” DOST-PHIVOLCS said in an advisory at 10 a.m. on December 18, 2024.
DOST-PHIVOLCS thus strongly recommends increased vigilance and readiness of communities in pre-determined zones of lahar and related hazards on these volcanoes.
Prolonged and heavy rainfall may generate post-eruption lahar on major channels draining Kanlaon Volcano by incorporating loose material from remnant pyroclastic density current (PDC) deposits of the December 9, 2024 explosive eruption.
Potential lahar and sediment-laden streamflows may occur along the Tamburong Creek in Biak-na-bato and Baji-Baji Falls and Talaptapan Creek, in Cabacungan, La Castellana town.
Post-eruption lahar similar to the June 5, 2024 lahar can affect these and communities downstream of these creeks.
Heavy rainfall may also generate post-eruption lahar on major channels draining Mayon Volcano by incorporating loose material from remnant PDC deposits from the January-March 2018 eruption.
The bulk of erodible PDC deposits occupy the watershed areas of the Miisi, Mabinit, Buyuan, and Basud Channels.
In addition, older and erodible eruption deposits on the watershed areas of the eastern and western slopes of the edifice and can be remobilized as non-eruption lahar by erosion of banks and channel beds.
Lahar can threaten communities downstream of the above channels with inundation, burial and wash away.
Potential lahar and sediment-laden streamflows may occur along the Miisi, Binaan, Anoling, Quirangay, Maninila, Masarawag, Muladbucad, Nasisi, Mabinit, Matan-ag, Basud, and Bulawan Channels in Albay Province, PHIVOLCS has further warned.
