On Sunday, officials in Indonesia moved 24,000 people on the vacation island of Bali away from the smoking Mount Agung volcano, as it sent thick plumes of grayish-black smoke into the blue sky above the tropical island.

Indonesia’s National Disaster Management Agency reported that the ashy smoke erupted more than 2.5 miles into the sky when the eruptions began and the smoke eventually rose to nearly 5 miles high.

The eruption began a little after 5 p.m. local time on Saturday (4:30 a.m. Eastern time in the U.S.) and kept going through Sunday.

Mount Agung is 9,944 feet high and last erupted in 1963, when on February 18 of that year it began a 20-day eruption and lava flows destroyed villages around it, killing an estimated 1,500 people.

Then, in September, predictions based on tremors in the area signaled that it may erupt again.

Read more: In Indonesia, Massive Bali Volcano Mount Agung Prepares to Erupt

“The chance that an eruption will happen is quite big. But it cannot be predicted when it will happen,” said Indonesia’s National Agency for Disaster Management spokesman Sutopo Purwo Nugroho back in September.

It turns out that it might happen now. Residents are being told to stay at least 7.5 kilometers (4.66 miles) away from the volcano.

On Sunday, Sutopo said that Lombok International Airport had been closed because of the volcanic ash, and would remain closed through 6 p.m. local time on Monday.

This was the street view of the volcano eruption on Sunday:

This newsreel from 1963 shows Mount Agung erupting and its effects. “People who dwelt near Agung pray to their gods whose wrath think brought on the eruption,” declares the narrator.

Mount Agugn does hold significance for people who practice the Hindu, Jain, and Buddhist faith. Some believe it’s the Earthly replica of Mount Meru, a sacred mountain in the stars that is believed to be the center of all physical and spiritual universes.

Bali is home to more than 4.2 million people across it’s 2,232 square miles, of which Agung is the highest peak.