Based on its Severe Weather Bulletin # 6 issued at 11:00 AM today (November 10, 2020), the Philippine Atmospheric Geophysical and Astronomical Services Administration (PAGASA) has placed Bicol Region under Tropical Cyclone Warning Signal # 1 from Typhoon “ULYSSES” and is further expected to intensify.  The typhoon is projected to make landfall over the Bicol Region tomorrow afternoon or evening (November 11, 2020). As such the Bicol Region is expected to experience moderate to heavy rainfall beginning tomorrow.

 

Due to this development, communities in pre-determined areas of lahar hazards from Mayon Volcano are strongly urged to be vigilant, ready and prepared to take action for their safety. The incoming typhoon is expected to bring about prolonged and heavy rainfall which may generate post-eruption lahars along major channels draining the Mayon Volcano edifice by incorporating loose material from thick pyroclastic density current (PDC) deposits from the 2018 eruption. The bulk of erodible PDC deposits currently occupy the watershed areas of the Anoling, Miisi, Binaan, Mabinit, Buyuan, Lidong and Basud Channels. In addition, older and erodible eruption deposits occupy the watershed areas on the eastern and western slopes of the edifice and continue to be remobilized as non-eruption lahars, particularly along the Masarawag-Maninila Rivers and downstream distributaries, by erosion of banks and channel beds. Mayon lahars can threaten communities along the middle and lower slopes and downstream of these channels with inundation, burial and wash away. All the above channels are currently choked with sediment, gravel and boulders brought down by lahars generated by Typhoons “Quinta” and “Rolly,” resulting in shallowed and shifting potential lahar paths with increased risk to already impacted communities as well as those adjacent to these.

DOST-PHIVOLCS, therefore, warns of potential lahars and sediment-laden streamflows on all river channels draining the slopes of Mayon Volcano that may be generated by heavy rainfall brought about by Tropical Cyclone “ULYSSES.” Local government units of communities at risk in Albay are strongly advised to be prepared and to move residents to high ground should heavy rains occur.

 

 

DOST-PHIVOLCS