Bulusan Volcano in Sorsogon erupted early Monday, prompting authorities to raise its alert level due to heightened volcanic activity, the Philippine Institute of Volcanology and Seismology (Phivolcs) reported.

The eruption, which began at 4:36 AM and lasted approximately 24 minutes, produced a bent plume that rose around 4,500 meters above the crater before drifting west to southwest. Infrasound sensors detected the activity, and local officials reported rumbling sounds about 15 minutes before the eruption.

In response to the eruption and the resulting ash emissions, the Civil Aviation Authority of the Philippines (CAAP) issued a Notice to Airmen (NOTAM), advising pilots to avoid flying near Mount Bulusan. The advisory covers the airspace from the surface up to 21,000 feet and will remain in effect from 28 April 2025, at 8:29 AM until 29 April 2025, at 4:36 AM.

Eric Apolonio, CAAP chief information officer and spokesperson, emphasized the importance of steering clear of the volcano’s summit, warning that ash from sudden phreatic eruptions poses significant risks to aircraft.

Phivolcs also cautioned residents living in valleys and along river or stream channels — particularly in the southeast, southwest, and northwest sectors of the volcano — to stay alert for possible sediment-laden stream flows and lahars, especially during periods of heavy or prolonged rainfall.

Ashfall health risks

The Department of Health (DOH) has warned residents in Sorsogon province to take precautions against the adverse effects of ashfall from Bulusan Volcano.

In an advisory, the agency urged the public to stay away from the volcano's 4-kilometer permanent danger zone and to avoid exposure to "fine and very small volcanic ash."

“Ang ashfall ay maaaring pumasok sa baga — kung ang komunidad ay nakaranas nito, magsuot ng face mask, pantakip ng mata, long-sleeves at pantalon (Ashfall can enter the lungs — if the community experiences ashfall, wear a face mask, goggles, long-sleeves, and pants for protection)” the DOH said.

In case of evacuation, residents are advised to prepare a "Go Bag" containing water, food, clothes, medicines, and a first aid kit.

For medical emergencies, the public may contact the National DOH Hotline at 1555 (press 2), the Public Health Preparedness and Response Unit at (052) 742-5555 local 5017, or the HEMS Operation Center at 0916-234-9063.

Authorities continue to monitor Bulusan Volcano closely as precautionary measures remain in place.