Lahar flowed down the slopes of Bulusan Volcano in Sorsogon province amid heavy rains and thunderstorms on Sunday, June 26, the Philippine Institute of Volcanology and Seismology (Phivolcs) said on Monday, June 27.

“A small-volume lahar that began at approximately 7:04 p.m., yesterday June 26, was detected by seismic and infrasound stations of the Bulusan Volcano Network (BVN). The event lasted fifty-four (54) minutes during a period of thunderstorm over Sorsogon Province,” Phivolcs said in a lahar advisory.

Based on the ocular investigation by the Bulusan Volcano Observatory, it has confirmed thin channel-confined lahar deposits along Calang Creek in Barangay Cogon, Irosin town—a major water channel down the southwestern slopes of Bulusan.

Phivolcs said the active volcano remains under Alert Level 1, which means it is still in an “abnormal” condition.

Bulusan Volcano’s status has been raised from Level 0 to Level 1, following a phreatic eruption on June 5. It had another phreatic eruption on June 12.

In an advisory issued on June 20, Phivolcs warned of another possible eruption “within the next few hours to the next few days.”

Phivolcs said that entry into the four-kilometer permanent danger zone is strictly prohibited due to possible sudden steam-driven or phreatic eruptions.

Meanwhile, the public is advised to remain vigilant when entering the two-kilometer extended danger zone, which is in the southeast sector of Bulusan Volcano.

Furthermore, people living within valleys and along river/stream channels especially on the southeast, southwest and northwest sector of the edifice were advised to be vigilant against sediment-laden stream flows and lahars in the event of heavy and prolonged rainfall should another phreatic eruption occurs.