Phivolcs warns of Mayon, Kanlaon lahar as Ada brings rains

MANILA, Philippines — The Philippine Institute of Volcanology and Seismology (Phivolcs) yesterday warned of possible lahar flows at Mayon and Kanlaon volcanoes as Tropical Storm Ada brings heavy to intense rainfall over Luzon and the Visayas.

As of 4 p.m., Ada was located about 255 kilometers east-northeast of Borongan City, Eastern Samar, with maximum sustained winds of 65 kilometers per hour and gusts of up to 80 kph, according to the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA).

The storm is forecast to affect the eastern coast of Southern Luzon until today, bringing 100 to 200 millimeters of rainfall that could trigger volcanic sediment flows, muddy streamflows, and runoff in rivers and drainage systems around Mayon.

At Mayon, PHIVOLCS said heavy rains may generate syn-eruption lahars along major channels draining the southern to eastern slopes of the volcano by remobilizing loose materials from new pyroclastic density current deposits in the Mi-isi, Bonga and Basud gullies.

Hot, in-channel lahars may occur in Mi-isi and Binaan in Daraga; Mabinit, Bonga, Matanag, Buyuan and Padang in Legazpi City; and Lidong and Basud rivers in Sto. Domingo.

These flows can cause scalding upon contact and pose serious life-threatening hazards.

Older eruption deposits on the southwestern slopes may also be remobilized into non-eruption lahars in Masarawag, Maninila, and related channels in Guinobatan.

PHIVOLCS warned that downstream communities could face inundation, debris impact, burial, and washout, particularly along the eastern slopes.

Meanwhile, Kanlaon Volcano in Negros remains at Alert Level 2.

PHIVOLCS warned that light to moderate, occasionally heavy rains from Ada could generate lahars and sediment-laden streamflows on the southern, western, and eastern slopes.

Recent ash emissions and pyroclastic deposits, as well as weakened upper slopes from Typhoon Tino last November, make the area prone to post-eruption and non-eruption lahars.

Communities along affected channels in Bago City, La Carlota, La Castellana, Moises Padilla, San Carlos City and Canlaon City may face destructive flows, strong debris impact, inundation, burial and possible washouts.

PHIVOLCS advised residents and local government units in high-risk areas to closely monitor weather updates and implement preemptive measures to ensure public safety.

Tropical Storm Ada has caused widespread travel disruptions nationwide, grounding flights and leaving thousands of passengers stranded at ports amid hazardous weather.

The Land Transportation Franchising and Regulatory Board on Friday urged bus and transport operators to suspend trips to Sorsogon and nearby areas, including Matnog Port, to ensure the safety of passengers and drivers.

LTFRB chief Vigor Mendoza II advised motorists and passengers to postpone travel until conditions improve.

The Philippine Coast Guard reported at least 5,376 passengers stranded across 21 ports

The Civil Aviation Authority of the Philippines reported the cancellation of 16 domestic flights on Friday, affecting some 1,008 passengers. — Gilbert Bayoran, Rudy Santos, Bella Cariaso