Dramatic footage showed a lightning storm swirling around a volcano in the Philippines early Monday after it began spewing lava. A slow flow of lava has begun seeping out of the Taal volcano—around 45 miles south of the capital Manila—the day after it belched out a huge plume of ash that triggered the evacuation of 8,000 people. The Philippine Institute of Volcanology and Seismology said the volcano is in “a period of intense unrest” that has seen “weak lava fountaining accompanied by thunder and flashes of lightning.” Authorities are warning that a “hazardous eruption” could take place at any moment that would feature “flows of ashes, rocks, gas at speeds of more than 60kph horizontally.” Experts have also warned of a possible “volcanic tsunami,” which could be caused by falling debris following an eruption. More than 450,000 people are estimated to live within the 14km danger zone of the Taal volcano.