ILOILO City – Authorities are raising the alarm over the threat of lahar flows from Mount Kanlaon as the southwest monsoon intensifies, bringing intermittent heavy rainfall across Negros Island.
The Philippine Institute of Volcanology and Seismology (PHIVOLCS) has urged heightened vigilance among residents and local government units (LGUs) around the volcano, warning that continued rains brought by the habagat (southwest monsoon) could trigger deadly lahars — fast-moving flows of volcanic debris, ash, and water.
“Occasionally heavy rains over Negros Island for the next few months could generate lahars in the rivers draining the southern Kanlaon edifice,” PHIVOLCS said in a lahar advisory issued on June 6.
The advisory came after netizens and local officials reported lahar flows in La Castellana, Negros Occidental, particularly along Buhangin River near Hacienda 92 Bridge in Barangay Sag-ang and in Ibid Creek, Barangay Biak-na-Bato.
The flows, described as cement-like and cohesive, were triggered by moderate to heavy rains brought by a low-pressure area and the southwest monsoon.
The Kanlaon Volcano Observatory in La Carlota City recorded 45.5 mm of rainfall over just 3.5 hours on the southern slopes of the volcano on Friday afternoon, Jun e 6, while more intense rainfall likely occurred near the summit — enough to remobilize volcanic debris.
PHIVOLCS warned that lahars could inundate and bury communities along the middle and lower slopes, urging pre-emptive action as heavy rainfall remains the only early warning for such events.
“These communities and local government units (LGUs) are advised to continually monitor weather conditions and take pre-emptive response measures when heavy rains are expected or have begun over the upper slopes of Kanlaon Volcano, for their safety,” the advisory read.
The Office of Civil Defense (OCD) Region 6 has also released its own alert, calling on residents near rivers and streams around the volcano to avoid riverbanks, remain alert for sudden lahar flows, and follow evacuation orders from local authorities.
“Stay vigilant and prioritize safety. Monitor official sources for updates,” OCD-6 emphasized.
Mount Kanlaon remains under Alert Level 3 (magmatic unrest), meaning it continues to show heightened volcanic activity, with increased chances of short-lived, moderately explosive eruptions.
PHIVOLCS has strongly recommended that communities within the six-kilometer Permanent Danger Zone (PDZ) remain evacuated.
The public is also reminded to prepare for ashfall, which can pose serious health risks. Vulnerable groups — including children, the elderly, pregnant women, and people with respiratory or heart conditions — are advised to wear masks or use damp cloths when ash is present.
Local governments are urged to maintain readiness for a possible escalation in volcanic activity that could lead to a hazardous eruption, and to continue preparing communities within the hazard zones for rapid evacuation.
Aviation authorities are likewise advised to warn pilots against flying near Kanlaon’s summit, as sudden ash emissions could endanger aircraft./PN
