Residents of the island of Luzon in the Philippines have been lying in nervous wait after seismologists predicted last week that its Mayon volcano was exhibiting signs of an "imminent eruption." On Monday, the prospect of danger was raised further, with the threat level jumping from three to four (on a scale that goes from one to five) after explosions rocked Mayon and caused "fountains of lava" to burst from its summit, Live Science reports. And the eventual eruption is predicted to be "violent," government officials say. "The public is strongly advised to be vigilant and desist from entering this danger zone," the Philippine Institute of Volcanology and Seismology warned in a statement, noting that danger zone had been expanded to a 5-mile radius from where the summit vents.
Pilots whose flights haven't been canceled are being advised not to fly anywhere near the summit, as spit-out ash can pose risks to planes. An ash plume has already stretched 4,300 feet into the air as a result of the lava bursts, a press release from the Philippines' Office of Civil Defense notes, per CNN. "It was like nighttime at noon, there was zero visibility in some areas because the ash fall was so thick," a local disaster response official tells ABC News. A Civil Defense rep adds that more than 24,000 locals have been moved to evacuation shelters, and another 3,100 or so have gone to hunker down with family and friends. A provincial governor advises everyone in the vicinity to cover their faces with masks (more than 30,000 have been handed out) and stay inside; schools in the area are all closed. Officials say there have been no reports of injuries. (Read more volcano stories.)