Thursday, November 7, 2013

Phivolcs warns that intense rain could trigger lahar flows, landslides in communities near Mt. Mayon

LEGAZPI CITY, Nov. 7 (PNA) -- The Philippine Institute of Volcanology and Seismology (Phivolcs) warned thousands of villagers living along river channels surrounding the slopes of Mt. Mayon volcano that heavy rains spawned by supertyphoon "Yolanda" (international name: Haiyan) that may hit Bicol on Friday could cause severe lahar flows and landslides.

Alex Baloloy, Phivolcs resident volcanologist, told members of the Regional Disaster Risk Reduction and Management Council (RDRRMC) on Thursday that millions of cubic meters of lahar threaten downstream communities along river channels bordering the slopes of the 2,463 meters high volcano in Albay.

Baloloy said with 10mm to 30mm rains to pelt the province every hour, these can breach the lahar deposits and pyroclastic materials deposited along river channels -- threatening communities along these water channels.

Albay Gov.Joey Salceda, citing lahar-threatened villages, said 22,622 families or 103,193 people in the towns of Malilipot, Bscacay, Sto. Domingo, Daraga, Camalig and Guinobatan as well as the cities of Ligao and Legazpi are endangered by possible lahar flows.

Salceda said “we have started evacuating people along these areas threatened by mud flows and lahar.” He said 165 barangays are prone to landslides while 67 barangays could be affected by mudflows or lahar flows. A total of 484 barangays in Albay, involving 299,396 individuals, in flood-prone areas, could be possibly affected by floods.

Baloloy said extreme rainfall may trigger landslides and excessive erosion of old pyroclastic deposits in the slopes of Mayon volacano. He said river channels that are silted with lahar are in Masarawag and Maninila in Guinobatan; in Buyuan, Padang and Mabinit in Legazpi City; Lidong and Basud in Sto. Domingo; Miisi and Anoling in Daraga and Nabonton channel in Ligao City.

Debris flows during heavy rain may trigger landslides in Mt.Masaraga, an old volcanic edifice north of Mayon volcano, and the debris flows may cascade down the Gabon river and other streams, threatening the town of Polangui -- similar to what happened on July 11, 2011 during tropical storm "Juaning."

The Phivolcs recommended the pre-emptive evacuation of communities in zones of high lahar hazards in Mt. Mayon for the duration of the passage of supertyphoon Yolanda.(PNA)