Authorities on the Indonesian tourist island of Bali have raised the volcano alert to the highest level as Mount Agung continues to churn and belch menacing-looking ash and smoke.
Landslides of lahar, wet volcanic debris, are making muddy trails down the volcano's slopes.
Officials have extended the danger zone around the rumbling volcano to 10 kilometers in places, a move that means as many as 100,000 people who live near the volcano need to evacuate.
Sutopo Purwo Nugroho, spokesman for the National Disaster Mitigation Agency, warned residents that lava, the molten, fluid rock a volcano emits, "will certainly spill over to the slopes."
Officials says blasts from the volcano can be heard miles away and flames can be seen at the peak.
Ash from the volcano forced officials to close the resort island's airport early Monday, canceling 445 flights and disrupting travel for 59,000 people. Frustrated passengers say they had no prior warning.
Reuters reports some stranded travelers in Bali are making the best of the situation and have gone to Mount Agung's observatory post to witness the eruption.
Bali is Indonesia's top tourist destination, with its Hindu culture, surf beaches and lush green interior attracting about 5 million visitors a year.
Mount Agung began rumbling and sending ash clouds into the sky on Tuesday.
Indonesia lies on the Pacific "Ring of Fire," where tectonic plates crash, which causes frequent volcanic and seismic activity.
Mount Agung last erupted in 1963, killing more than 1,000 people.
Mount Sinabung on Sumatra Island, active since 2013, is also at its highest alert level.