• GILBERT P. BAYORAN
Anticipating light to moderate, with occasionally heavy rains due to Tropical Storm “Ada”, the Philippine Institute of Volcanology and Seismology (PHIVOLCS) warned of possible lahar flows in rivers and drainage areas on Kanlaon Volcano, which remains at Alert Level 2, as of this time.
This developed as blue alert status is now being observed by the Provincial Disaster Risk Reduction Management Council Emergency Operations Center (PDRRMC), in relation to the tropical storm.
At the same time, the PDRRMC also issued an advisory, which called on the public to be cautious of possible ash fall emitted by Kanlaon Volcano, which spewed ash on Friday, that drifted towards a southerly direction.
On Thursday, two ash emissions were observed at Kanlaon Volcano, along with the occurrence of 46 volcano-tectonic quakes.
In a statement, PHIVOLCS said prolonged heavy rainfall could generate life-threatening lahars and sediment-laden streamflows on major channels draining the southern, western and eastern slopes of Kanlaon Volcano.
Post-eruption lahars can be generated by heavy rainfall eroding loose material from remnant pyroclastic density current (PDC) deposits of recent explosive eruptions and loose ashfall mostly from recent ash emission events, it added.
In addition, non-eruption lahars could be generated when areas on the upper slopes that have been recently exposed by landslides or weakened during the passage of Typhoon Tino in November last year, become susceptible to failure, and feed to rivers that have already delivered destructive flows to downstream communities, the PHIVOLCS advisory further said
Communities in Bago City, La Carlota City, La Castellana, Moises Padilla, and San Carlos City in Negros Occidental, and Canlaon City in Negros Oriental that are situated along the following channels may be affected by lahars and sediment-laden streamflow and related flooding and siltation.
PHIVOLCS warned that Kanlaon lahars, were shown by Typhoon Tino to be strong enough to transport enormous volumes of gravel and boulders, and could threaten communities by their force of impact, inundation, burial, and wash out.*
