LEGAZPI CITY, Albay, Philippines — Prolonged and heavy rainfall due to Typhoon Tisoy may cause post-eruption lahar to flow in rivers that run down the slopes of Mayon Volcano in Albay and Mount Bulusan in Sorsogon, according to a warning issued on Saturday by the Philippine Institute of Volcanology and Seismology (Phivolcs).
Mount Mayon is still on alert level 2, while alert level 1 is still in effect over Mount Bulusan.
Starting on Monday, the Bicol region may have moderate to heavy rains and thunderstorms brought by Tisoy, which entered the Philippine area of responsibility (PAR) Saturday, according to the Philippine Atmospheric, Geophysical, and Astronomical Services Administration (Pagasa).
This may cause lahar and sediment-laden streamflows on the slopes of the two volcanos.
At Mayon, the channels in danger of potential lahar are Miisi, Mabinit, Matag-an, Basud, Masarawag-Maninila, and Quirangay.
At Bulusan, the rivers under threat are Malunoy, Mapaso, Cadac-an, Tinampo, and Cogon.
“Communities and local government units beside these drainages are advised to be additionally vigilant and to move residents to high ground when heavy rains occur,” Phivolcs advised in the bulletins.
Phivolcs also reminded residents near Bulusan to avoid entering its 4-kilometer permanent danger zone (PDZ) to avoid harm.
/atm