Based on the Tropical Cyclone Bulletin #18 issued at 05:00 PM today by the Philippine Atmospheric Geophysical and Astronomical Services Administration (PAGASA), Supertyphoon “KARDING” is expected to bring heavy to intense with at times torrential rains this evening through tomorrow early morning over Metro Manila and portions of CALABARZON and Central Luzon. These rains could generate volcanic sediment flows or lahars, muddy streamflows or muddy run-off in rivers and drainage areas on Pinatubo and Taal volcanoes. 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 intense rainfall may generate non-eruption lahars on major rivers draining western Pinatubo Volcano where significant deposits of the 1991 PDCs remain on the watershed. Pinatubo lahars are likely be channel-confined and occur on the upper to middle reaches of the Sto. Tomas- Marella and Bucao River systems but may transition to muddy streamflows and floods on the lower reaches and affect adjacent communities of San Marcelino, San Narciso, San Felipe and Botolan, Zambales Province. 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.
Prolonged and heavy rainfall may also generate muddy streamflow and muddy runoff around Taal Volcano, particularly on the slopes on the western Taal Caldera where thin remnant ash can be remobilized in streams and roads and overland of the lakeward slopes. In particular, muddy streamflow and runoff can recur on previously affected communities of Agoncillo and Laurel, Batangas Province. In addition to this, extensive fissures on the northeast and southwest sectors of Taal Caldera generated by the 2020 eruption may be eroded and enlarged by heavy rains, as was the case in previous typhoons when even previously undetected fissures emerged and caused damages to overlying or adjoining buildings and houses. The eruption fissures occur in the Municipalities of Agoncillo, San Nicolas, Lemery and Taal on the southwest caldera, and in the Cities of Talisay and Tanauan on the northeastern side. Potential fissure enlargement with rains brought by Supertyphoon “KARDING” may cause structural damage or even collapse of structures that are situated right on or beside the fissure traces.
DOST-PHIVOLCS strongly advises the communities and local government units of the above identified areas of risk to continually monitor the storm conditions and take pre-emptive response measures for their safety from “KARDING.”
DOST-PHIVOLCS
