Mount Lewotobi Laki-laki erupts, as seen from Nangahale village in Sikka, East Nusa Tenggara on July 7, 2025. ARNOLD WELIANTO/AFP via Getty Images

Indonesia's rumbling Mount Lewotobi Laki Laki erupted twice on Monday, sending a column of volcanic materials up to 11 miles into the sky, dumping ash on villages and causing dozens flight cancellations.

No casualties were immediately reported. The volcano on Flores island has been at the highest alert level since an eruption on June 18, and an exclusion zone was doubled to a 4.3-mile radius as eruptions became more frequent.

Indonesia's Geology Agency recorded an avalanche of searing gas clouds mixed with rocks and lava traveling up to 3 miles down the slopes of the 5,197-foot mountain. Observations from drones showed lava filling the crater, indicating deep movement of magma that set off earthquakes.

The initial column of hot clouds that rose just after 11:00 a.m. local time (0305 GMT) was the volcano's highest since a major eruption in November 2024 that killed nine people and injured dozens, said Muhammad Wafid, the Geology Agency chief. It also erupted in March.

"An eruption of that size certainly carries a higher potential for danger, including its impact on aviation," Wafid told The Associated Press. "We shall reevaluate to enlarge its danger zone that must be cleared of villagers and tourist activities."

In a statement, Wafid urged the public and tourists to stay at least four miles from the eruption, remain calm and follow the directions of the local government.

"The public is asked not to believe information from unclear sources," Wafid said. "In addition, people around disaster-prone areas should be aware of the potential for lava floods if heavy rain occurs.".

The volcano erupted again just after 7:30 p.m. (1100 GMT), spewing lava and sending clouds of ash up to 8 miles into the air, according to the Center for Volcanology and Geological Disaster Mitigation.

By Monday afternoon, at least 24 flights between Bali and Australia, Singapore and South Korea were cancelled and many others were delayed. Flights on four domestic routes were cancelled, said Ahmad Syaugi Shahab, spokesperson for Bali's Ngurah Rai international airport.

He said the airport was running normally despite the cancellations, as monitoring showed the volcanic ash had not affected Bali's airspace.

"Several airlines serving the routes to Labuan Bajo (on Flores), Australia, Singapore, and South Korea have confirmed cancellations and delays," he said in a statement.

He said the airlines included Virgin Australia, Jetstar Airways and AirAsia Indonesia.

Australia's Jetstar said several flights were cancelled "due to volcanic ash caused by an eruption of Mount Lewotobi."

Falling ash after the initial eruption blanketed several villages with debris and blocked sunlight for almost half an hour, Hadi Wijaya, head of the Center for Volcanology and Geological Disaster Mitigation, said in a statement.

He said volcanic materials, including thumb-size fragments of gravel and ash, were thrown up to 5 miles from the crater. He warned residents to be vigilant about heavy rainfall that could trigger lava flows in rivers originating from the volcano.

Photos and videos circulated on social media showed the ash cloud expanding into a mushroom shape as tons of volcanic debris covered houses up to their rooftops in nearby villages. Some residents ran in panic under the rain of volcanic material or fled with motorbikes and cars.

Monday's eruptions were the result of the accumulation of energy due to a blockage of magma in the crater, which reduced detectable seismic activity while building up pressure, Wijaya said.

The initial eruption was one of Indonesia's largest since 2010 when Mount Merapi, the country's most volatile volcano, erupted on the densely populated island of Java. That killed 353 people and forced over 350,000 people to evacuate.

Indonesia is an archipelago of more than 280 million people with frequent seismic activity. It has 120 active volcanoes and sits along the "Ring of Fire," a horseshoe-shaped series of seismic fault lines encircling the Pacific Basin.

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