KARANGASEM, Indonesia -- Bali's international airport was reopened on Wednesday, although a volcano on the island is still erupting. Indonesia's president has urged anyone still within the exclusion zone to get out "for the sake of their safety."

Airport spokesman Arie Ahsannurohim said ash from the Mount Agung volcano had drifted south and southeast, leaving clean space above the airport for planes to land and take off. The reopening came Wednesday afternoon in Indonesia.

The airport had been closed since Monday morning, disrupting travel for tens of thousands of people.

President Joko "Jokowi" Widodo ordered all concerned ministries and agencies, as well as the military and police, to help the Bali government cope.

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Authorities on Monday told 100,000 people to leave an area extending up to six miles from the volcano. Some though have stayed.

Airport spokesman Ari Ahsanurrohim said more than 440 flights were canceled Tuesday, affecting nearly 60,000 passengers, about the same as Monday. Without aircraft, getting in or out of Bali requires traveling hours by land and taking a boat to another island, enduring choppy seas in Bali's rainy season.

Ahsanurrohim said Wednesday morning that volcanic ash had not been detected at the airport yet, but observations from the Darwin Volcanic Ash Advisory Center showed the ash had reached an altitude of 25,000 feet.

Mount Agung volcano is seen spewing smoke and ash in Bali, Indonesia, on Nov. 26, 2017, in this picture obtained from social media. Reuters

"I don't know, we can't change it," said stranded German traveler Gina Camp earlier on Wednesday, who planned to go back outside and enjoy another day on the island, which attracts about 5 million visitors a year to its famed resorts and world-class surf spots. "It's nature and we have to wait until it's over."

Experts said a larger, explosive eruption is possible -- or Agung could stay at its current level of activity for weeks.

"If it got much worse, it would be really hard to think of. You've got a huge population center, nearly a million people in Denpasar and surroundings, and it's very difficult to envision moving those people further away," said Richard Arculus, a volcano expert at Australian National University, adding that an eruption in 1843 was even more explosive than the one in 1963.

"There are many examples in history where you have this kind of seismic buildup - steam ejections of a little bit of ash, growing eruptions of ash to a full-scale stratosphere-reaching column of ash, which can presage a major volcanic event," he said.

A NASA satellite detected a thermal anomaly at the crater, said senior Indonesian volcanologist Gede Swantika. That means a pathway from the storage chamber in the volcano's crust has opened, giving magma easier access to the surface.

Indonesian officials first raised the highest alert two months ago when seismic activity increased. More than 100,000 people living near the volcano fled their homes, many abandoning their livestock or selling them for a fraction of the normal price. The activity decreased by late October, and the alert was lowered before being raised to the highest level again Monday.

Nearly 40,000 people are now staying in 225 shelters, according to the Disaster Mitigation Agency in Karangasem. But tens of thousands of villagers have remained in their homes because they feel safe or don't want to abandon their farms and livestock.

"Ash has covered my house on the floor, walls, banana trees outside, everywhere" said Wayan Lanus, who fled his village in Buana Giri with his wife and daughter.

Flows of volcanic mud have been spotted on Agung's slopes, and Arculus warned more are possible since it's the rainy season.

"They're not making a lot of noise. It's just suddenly coming like a flash flood out of nowhere," he said. "You do not want to be near them. Stay out of the valleys."

Indonesia sits on the Pacific "Ring of Fire" and has more than 120 active volcanoes.