LEGAZPI CITY: The Philippine Institute of Volcanology and Seismology (Phivolcs) has warned disaster officials and responders to be on guard as re-mobilization of volcanic debris from the slopes of Mounts Mayon in Albay and Bulusan in Sorsogon threatens the communities around them once super typhoon “Ruby” makes landfall on Saturday.
Ed Laguerta, Phivolcs chief resident volcanologist in Bicol, said during the Provincial Disaster Risk Reduction and Management Council emergency briefing here on Thursday afternoon that lahar flows will hit low-lying areas due to typhoon with heavy-to-intense rainfall.
“Most probably the remnants of the 2006 eruption and in quarrying sites of volcanic debris will cause the re-mobilization of lahar in low lying-areas near Mayon volcano,” said Laguerta. “Based on Phivolcs study, a 6-mm-per-hour precipitation could initiate re-mobilization of volcanic materials.”
Based on Phivolcs advisory issued at 3:00 p.m. Thursday, lahar flows from the slopes of two most active volcanoes in Bicol is expected to cascade down to low-lying areas once “Ruby” makes landfall on Saturday.
It said typhoon “Ruby” is estimated to bring heavy-to-intense amount of rainfall within its 700-km-diameter coverage area, thus, posing grave threat of extreme rainfall-induced landslides and lahar in volcanic edifices, particularly in Albay and Sorsogon Provinces.
In Albay province, extreme rainfall may trigger landslides and excessive erosion of old pyroclastic deposits in the upper-to-middle slopes of Mayon Volcano, generating lahar in all river drainage.
Potentially, large-magnitude lahar can threaten downstream communities along river channels with inundation, burial and washout.
The greatest lahar hazard can consequently be faced by communities along the Masarawag (Guinobatan), Maninila (Guinobatan), Buyuan-Padang (Legazpi City), Lidong (Sto. Domingo), Mabinit (Legazpi City), Basud (Sto. Domingo), Miisi (Daraga), Anoling (Daraga) and Nabonton (Ligao City) channels.
Furthermore, lahar-related flooding, washout and siltation can subsequently occur along the Yawa River, threatening adjacent and low-lying areas of Legazpi City.
In Sorsogon province, extreme rainfall may cause excessive erosion of existing pyroclastic deposits in the upper slopes of Bulusan Volcano, triggering lahar in rivers draining the southeastern, southwestern and northwestern flanks.
Potential moderate-volume lahar can threaten downstream communities along the Malunoy (Patag), Mapaso, Cadac-an, Tinampo and Cogon Rivers in Irosin and the Añog-Rangas River in Juban.
The Phivolcs strongly recommended vigilance and readiness of communities in pre-determined zones of lahar hazards in the above volcanoes.
Preparedness on clearing and rehabilitation operations is also recommended in the event of debris deposition on roads and bridges that traverse lahar channels.
Similarly, the Phivolcs reiterated the strict implementation of no entry on the declared permanent danger zones in both Mayon and Bulusan volcanoes due to the potentially amplified dangers of rockfalls, avalanches, landslides and steam-driven explosions at the summit area.
The Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) in Bicol warned disaster officials and responders that with 700 diameter associated with heavy-to-intense precipitation, super typhoon “Ruby” (international name: Hagupit) will be causing massive landslides across the region, storm surges, and flashfloods, thus, re-mobilizing lahar flows from the restive Mayon volcano here.
“We are urging the public to take shelter before ‘Ruby’ makes landfall on Saturday. We urge sea, air and road travelers to cancel their trips ahead of time for safety,” said Lilian Guillermo, PAGASA Bicol officer-in-charge, before local chief executives of Albay, disaster officials and responders during the emergency meeting presided by Cedric Daep, chief of the Albay Public Safety Emergency Management Office here.
She said “Ruby” is expected to make a landfall on Saturday in Samar, passes through Sorsogon and the west coast area of Albay province with intense rainfall.
Daep said they will enforce evacuation ahead of time, specifically those people threatened by storm surges in coastal areas of Albay, lahar flows, flash floods and families with light houses materials.
PAGASA officials warned that three-to-four-meter high storm surges might pummel in coastal areas of the Visayas, specifically in Samar and the Bicol Region.
Daep recommended the no-sailing policy of all sea crafts starting Friday. –
The Albay official also urged the mayors to work closely with the barangay officials on the ground.
“Starting tomorrow, there must be no sailing. We need to evacuate ahead of time because we don’t want the repetition of super typhoon ‘Reming’,” Daep pointed out.
Office of Civil Defense Director and Regional DRRMC chairman Bernardo “Raffy” Alejandro said during the RDRRMC briefing held at the OCD -icol social hall that all disaster officials and responders are on heightened alert.
“The emergency management team is in place and on standby. We have prepositioned 500 bags of rice from NFA with on-going repacking of family food packs,” Alejandro said.
Albay Governor Joey Sarte Salceda ordered the cancellation of classes Friday to give way for typhoon evacuees.
“Don’t go to class unless you are evacuating. We need the classrooms and we have to clear and clean them. Use the time to prepare for a possibly two to three days of seclusion from bad elements. All levels, all areas, all types. Classes are suspended tomorrow (Friday) until lifted,” the governor said in his directive to disaster officials here Thursday.
Salceda also directed employees of the provincial government of Albay not to report to their respective offices, except for disaster response offices here.
“As a matter of policy, government employees in Albay must take care of their family preparations and should therefore not go to work,” he said, adding “But with exception of those directly engaged in disaster response, especially in the AFP, PNP, DOH, OCD in the national government and Provincial Health Office, hospitals, APSEMO, Provicnial General Services Office and Provincial Engineering Office and those units of LGUs as determined by their local government executives; those that requested prior and continuing exemption like the Bureau of Internal Revenue and Bangko Sentral ng Pilipinas.”
Salceda said it is understood that these agencies will do their tasks ahead or ask others to do these for them.
“I also strongly persuade the private sector to dismiss their employees after lunch,” the Albay governor said. PNA