Mount Agung on the Indonesian island of Bali began erupting on Saturday, prompting the closure of the island’s main airport. According to CNN, this has stranded thousands of tourists on the island, as well as forcing evacuations of more than 29,000 residents in the northeastern area of Bali.

The volcano began spewing ash, steam and smoke on Saturday, with fire and lava spotted near the summit. This caused Indonesia’s Center for Volcanology and Geological Hazard Mitigation to raise its aviation alert notice to “Red” (the highest level) on Sunday.

And on Monday, the National Agency for Disaster Management to issue a Level 4 alert, indicating the potential for another larger eruption. They have also recommended no public activities within 8 to 10 kilometers (about 5 to 6 miles) from the peak.

“While the sun is shining and there is little sign of volcanic ash in the southern regions of Bali, evidence of volcanic ash at higher altitudes on aviation approach and departure paths has prompted the decision to close the airport,” Bali Tourism Board Chairman Ida Bagus Agung Partha Adnyana said in a statement.

Ngurah Rai International Airport has been closed, canceling all flights inbound and outbound. It is expected that flights will be suspended through at least Tuesday, possibly longer.

Heavy rains are now starting to cause disastrous mudflows, and they could worsen as the volcano goes through the next phases of its eruption.

“The volcanic eruption has now moved on to the next, more severe, magmatic eruption phase, where highly viscous lava can trap gasses under pressure, potentially leading to an explosion,” Mark Tingay, a geologist at the University of Adelaide’s Australian School of Petroleum, said in a statement Monday.

Alerts were first raised back in September that Mount Agung could erupt at any moment. The last time the volcano erupted was 1963, killing more than 1,700 people.

Stay tuned to GrindTV for more updates on this story.

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