The Philippine Institute of Volcanology and Seismology (Phivolcs) on Sunday. Sept. 25, warned that lahars or mudflows may occur along rivers and drainages of Mt. Pinatubo and Taal Volcano due to super typhoon Karding’s expected heavy to torrential rains over Southern and Central Luzon.

Karding made its first landfall in the vicinity of Burdeos, Quezon at around 5:30 p.m., and is expected to traverse Central Luzon in the next few hours.

In an advisory issued at 7 p.m. on Sunday, Sept. 25, Phivolcs said Karding’s rains could generate volcanic sediment flows or lahars, muddy stream flows or muddy run-off along rivers and drainage areas around Pinatubo and Taal volcanoes.

“Pinatubo lahars are likely to 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 stream flows and floods on the lower reaches and affect adjacent communities of San Marcelino, San Narciso, San Felipe and Botolan, Zambales Province,” Phivolcs said.

“Muddy stream flows 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,” it added.

Meanwhile, Phivolcs said that prolonged and heavy rainfall may “generate muddy stream flow 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 stream flow and runoff can recur on previously affected communities of Agoncillo and Laurel, Batangas province,” it said.

Moreover, Phivolcs said that 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 in recent 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,” it added.

Phivolcs recommended an increased vigilance and readiness of communities in pre-determined zones of lahar and related hazards on Pinatubo and Taal volcanoes.

It also advised concerned communities and local government units to continue to monitor the storm conditions and take preemptive response measures for their safety.