MANILA, Nov. 24 -- The Philippine Institute of Volcanology and Seismology (Phivolcs) on Monday said the forecast heavy rains across Bicol Region could generate volcanic sediment flows or lahars from Mayon Volcano.

Muddy streamflows or muddy run-off in rivers and drainage areas are possible due to rains caused by Tropical Depression Verbena and the shear line.

"Phivolcs thus strongly recommends increased vigilance, readiness and if necessary, pre-emptive evacuation of communities in pre-determined zones of lahar and related hazards in the province of Albay," it said in an advisory.

Intense to torrential rainfall can generate life-threatening post-eruption lahars on major channels draining Mayon Volcano by eroding loose material from rem...