Mount Mayon had its fourth lava fountain eruption on the afternoon of 28 January 2018, the Philippine Institute of Seismology and Volcanology (Phivolcs) said. At 3:28 p.m., the Mayon spewed molten lava, and a 2-kilometer ash plume was generated from the crater of the restive volcano. However, officials said that they could not provide details yet on the height of the lava fountain for clouds were obscuring the view. Despite this, Phivolcs noted that a rumbling sound was heard at Ligñon Hill when Mayon spewed lava.
Phivolcs also said that people should watch out for lahar or sediment-laden stream flows in other river channels besides those of Buyuan, Miisi, Basud, San Vicente, Buang, Quirangay and Masarawag-Maninila. Phivolcs stated that it would take only 40 millimeters of sustained, heavy rain for an hour and a half for lahar to occur—and, with Albay currently experiencing scattered rainshowers, he said there was a very high possibility of lahar.