State volcanologists issued a lahar advisory on Saturday as the southwest monsoon, or Habagat, soaked western Luzon, warning that heavy rain could turn volcanic ash on Pinatubo and Taal into fast-moving mudflows in rivers and drains below.
What Phivolcs warned
In an 11 a.m. advisory, the Philippine Institute of Volcanology and Seismology (Phivolcs) said Habagat-induced rainfall over western and central Luzon could generate lahars, or volcanic sediment flows, plus muddy streamflow and runoff on the two volcanoes.
The agency urged communities inside lahar-hazard zones to stay vigilant and ready, and to take precautionary measures as the rains continue.
Which areas are at risk
Phivolcs named the specific river systems and the towns that may see mudflow or muddy runoff:
| Volcano | River system | Towns that may be affected |
|---|---|---|
| Pinatubo | Sto. Tomas-Marella and Bucao | San Marcelino, San Narciso, San Felipe, Botolan (Zambales) |
| Pinatubo | O’Donnell and Pasig-Potrero | Downstream communities in Tarlac and Pampanga |
| Taal | West and north slopes of Taal Lake | Agoncillo, Laurel, Talisay (Batangas) |
Why the danger is high now
Pinatubo still holds heavy deposits from its 1991 eruption, the world’s second-largest volcanic event of the 20th century. Phivolcs said prolonged, intense rainfall can wash these down as non-eruption lahars on rivers draining the volcano’s west side. At Taal, thin remnant ash on the slopes west and north of the lake can similarly turn into muddy runoff.
What residents should do
- Monitor Phivolcs and PAGASA bulletins and heed local government warnings.
- Keep clear of river channels, bridges and low-lying areas near the lahar zones above.
- Be ready for preemptive evacuation if your barangay sits inside a hazard zone.
The lahar alert comes as Luzon contends with widespread Habagat flooding, with PAGASA forecasting 5 to 7 more tropical cyclones before the year ends.
Taal has also been restive in recent weeks, logging dozens of volcanic earthquakes in a single 24-hour stretch.
