The Philippine Institute of Volcanology and Seismology (Phivolcs) reported heightened unrest at two of the country’s most active volcanoes this weekend, marked by fresh ash emissions on Negros Island and continuing lava flows in Albay province.

Kanlaon Volcano emitted a grayish ash plume that rose 800 meters above its crater at 5:53 a.m. Saturday. The ash drifted southwest, prompting warnings for local communities to remain vigilant against possible sudden steam-driven, or phreatic, explosions.

During the latest 24-hour monitoring period, Phivolcs recorded five volcanic earthquakes, including two volcanic tremors, and a highly elevated sulfur dioxide emission rate that peaked at 2,701 tons. Kanlaon remains under Alert Level 2, and entry into its 4-kilometer Permanent Danger Zone is strictly prohibited.

Meanwhile, Mayon Volcano remains under Alert Level 3, indicating intensified magmatic unrest. Now on its 151st consecutive day of effusive eruption, Mayon’s continuous lava effusion persisted through early Saturday morning, with active flows monitored during the 24-hour observation period ending at midnight.

Phivolcs reported that the incandescent flows have reached lengths of 3.8 kilometers along the Basud Gully, 3.2 kilometers along the Bonga Gully, and 1.6 kilometers along the Mi-isi Gully. The effusive activity was accompanied by minor Strombolian activity at 5:59 a.m. Friday and subsequent collapse-fed pyroclastic density currents later that morning.

Aviation authorities continue to prohibit flights near the summits of both volcanoes, as sudden airborne ash and ballistic fragments remain hazardous to aircraft.