By Brian Campued
The Philippine Institute of Volcanology and Seismology (Phivolcs) on Saturday urged communities surrounding Pinatubo and Taal volcanoes to heighten alert and preparedness as heavy rains brought by the southwest monsoon (habagat) continue to affect Luzon.
In its lahar advisory issued at 11:00 a.m., Phivolcs said the monsoon rains could result in volcanic sediment flows or lahars and muddy streamflows or muddy run-off in rivers and drainage areas on the two volcanoes.
According to Phivolcs, lahars in Pinatubo are “likely to be channel-confined and occur on the upper to middle reaches of the Sto. Tomas-Marella and Bucao River systems.”
However, these may transition into muddy streamflows and floods that may affect the communities of San Marcelino, San Narciso, San Felipe, and Botolan in Zambales.
“Muddy streamflows may likewise be generated along the O’Donnell and Pasig-Potrero River systems draining the Pinatubo edifice to the north and southeast, respectively and affect downstream communities in Tarlac and Pampanga Provinces,” Phivolcs said.
Prolonged and heavy rainfall may also generate muddy streamflow and muddy runoff around Taal Volcano, particularly on the slopes west of Taal Lake, affecting the towns of Agoncillo and Laurel in Batangas.
Phivolcs advised at-risk communities and local government units “to continually monitor the storm conditions and take preemptive response measures for their safety.”
Taal Volcano remains under Alert Level 1 (low-level volcanic unrest), while Pinatubo has been placed on Alert Level 0 (normal) since Aug. 12, 2021.
In its weather advisory issued at 11:00 a.m. on Saturday, the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) warned of moderate to intense rains over western and central Luzon over the long weekend due to the southwest monsoon.
The state weather bureau emphasized that forecast rainfall may be higher in mountainous and elevated areas, and that impacts may be worsened by significant antecedent rainfall.
-jpv
