Philippines monsoon rains trigger lahar warnings and flooding

Heavy rains brought by the southwest monsoon, or ‘habagat’, have triggered red rainfall warnings across Metro Manila and several provinces in Luzon, leading to flooding and infrastructure damage. In Tarlac, a portion of the Aquino Bridge collapsed due to strong river currents and continuous rainfall.

The Philippine Institute of Volcanology and Seismology (Phivolcs) has issued a lahar advisory for communities near the Pinatubo and Taal volcanoes. Heavy rainfall may cause volcanic sediment flows or lahars. In Pinatubo, these flows are expected in the upper to middle reaches of the Sto. Tomas-Marella and Bucao River systems, potentially affecting communities in Zambales, Tarlac, and Pampanga. Near Taal Volcano, muddy streamflows and runoff may affect the towns of Agoncillo and Laurel in Batangas.

Additionally, the La Mesa Dam is nearing its overflow elevation, sitting just 0.34 meters below the limit. Continued heavy rain is expected to raise water levels, posing a risk of overflow into the Tullahan River and affecting low-lying areas in Quezon City, Caloocan, Valenzuela, Malabon, and Navotas.