MANADO, Indonesia – Indonesian rescuers raced to evacuate thousands of people on April 18 after a volcano erupted five times, forcing the authorities to close a nearby airport and issue a warning about falling debris that could cause a tsunami.

The crater of Mount Ruang flamed with lava against a backdrop of lightning bolts overnight after erupting four times on April 17, forcing the authorities to raise its alert level to the highest of a four-tiered system.

The volcano on a remote island in Indonesia’s outermost region was still billowing a column of smoke in the morning on April 18, prompting the authorities to shut the nearest international airport in Manado city on Sulawesi island for 24 hours.

Houses on the neighbouring remote island of Tagulandang were riddled with holes from falling volcanic rocks, and residents were preparing to leave at least temporarily.

“The current condition, particularly the road condition, is covered by volcanic material,” local rescuer Ikram Al Ulah told AFP by phone from the Tagulandang seaport.

“Currently, many people are still wandering around. Maybe to evacuate precious goods from their house.”

The authorities said they were rushing to evacuate 11,000 residents from the area around Tagulandang, home to around 20,000 people.

Some residents were already trying to flee in a panic, according to officials.

“Last night, people evacuated on their own but without direction due to the volcano’s eruption and materials in the form of small rocks that fell, so the people scattered to find evacuation routes,” local search and rescue agency official Jandry Paendong said in a statement on April 18.

He said 20 staff were helping evacuate residents along the coastline near the volcano on rubber boats.

The authorities also evacuated a prison on Tagulandang island, ferrying 17 inmates along with 11 officials and 19 residents by boat to Likupang seaport in northern Sulawesi island, according to the rescuer Ikram.

The evacuation was requested by the prison chief because the facility sits directly across from the volcano, said the rescuer.

Tourists and residents were warned to remain outside a 6km exclusion zone.

More than 800 people were initially taken to safety from Ruang to nearby Tagulandang island after the first eruption on April 16, before four more eruptions on April 17 prompted evacuations from that island.

Mr Paendong called for more boats and equipment so that his team could “carry out evacuation for people in the coast or near the coast” facing the volcano.

Tsunami warning

The authorities also warned of a possible tsunami as a result of the eruptions.

“The communities in Tagulandang island, particularly those residing near the beach, (need) to be on alert for the potential ejection of incandescent rocks, hot cloud discharges and tsunami caused by the collapse of the volcano’s body into the sea,” Indonesian volcanology agency chief Hendra Gunawan said in a statement on April 17.

The authorities’ fears were compounded by previous experience.

In 2018, the crater of Mount Anak Krakatoa between Java and Sumatra islands partly collapsed when a major eruption sent huge chunks of the volcano sliding into the ocean, triggering a tsunami that killed more than 400 people and injured thousands.

Indonesia, a vast archipelago nation, experiences frequent seismic and volcanic activity due to its position on the Pacific “Ring of Fire”, an arc where tectonic plates collide that stretches from Japan through South-east Asia and across the Pacific basin.

The impact of Mount Ruang’s eruption led to the closure of Sam Ratulangi International Airport in Manado city, located more than 100km from the volcano, for 24 hours until the evening on April 18.

The airport runways were shut “due to the spread of volcanic ash which could endanger flight safety”, Mr Ambar Suryoko, head of the Manado region airport authority office, said in a statement.

The airport hosts airlines that fly to Singapore and cities in South Korea and China.

“All flights... impacted because the airport is affected by the eruption of Mount Ruang, volcanic ash,” 29-year-old Dimas, an airport officer in Manado, told AFP by phone.

In response to queries from The Straits Times, Changi Airport Group said flights to and from Bandar Seri Begawan in Brunei, as well as Kota Kinabalu, Kuching and Miri in Malaysia, may be affected as a result of the volcanic activity. These destinations are served by AirAsia, Royal Brunei Airlines, Scoot and Singapore Airlines.

It advised travellers to check the Changi Aiport website for the latest flight information, and those affected can contact the airlines for alternative arrangements.

Singapore budget carrier Scoot cancelled four flights that were scheduled to depart on April 18. The flights were between Singapore and Kota Kinabalu, and Singapore and Miri.

“Scoot apologises for the inconvenience caused. The safety of our customers and crew is our top priority,” Scoot said in response to queries.

“We will continue to monitor the situation in East Malaysia and will adjust our flight schedule as necessary,” Scoot said, adding that it is assisting affected customers.

Budget airline AirAsia cancelled flights to and from nine airports including Kota Kinabalu, Tawau, Sandakan, Labuan, Miri, Sibu, Bintulu, Kuching and Brunei after the Civil Aviation Authority of Malaysia issued a volcanic ash hazard warning on April 18.

Flights from 10am on April 18 until 8am on April 19 will be cancelled, AirAsia said in a release.

Flag carrier Malaysia Airlines said on Facebook that it cancelled 18 flights between Kuala Lumpur and Sabah, as well as Kuala Lumpur and Sarawak, on April 18. ST has contacted Malaysia Airlines for more information. AFP

• Additional reporting by Yong Li Xuan