The eruption of the biggest mountain on the island of Java caught locals by surprise on Saturday, sending thousands fleeing and forcing hundreds of families into makeshift shelters.
At least 11 villages of Lumajang district in East Java were coated in volcanic ash, submerging houses and vehicles, smothering livestock and leaving at least 900 evacuees seeking shelter in mosques, schools and village halls.
Dramatic footage showed Semeru pumping a mushroom of ash into the sky, looming over screaming residents of a nearby village as they fled.
“The death toll is now 13 people. Rescuers found more bodies,” national disaster mitigation agency spokesman Abdul Muhari told AFP, without specifying the cause of death.
Two of the victims have been identified, he said in a later statement.
At least 57 people including two pregnant women were injured in the eruption, of whom 41 suffered burns and were hospitalised, the agency said in a press release.
President Joko Widodo on Sunday ordered a rapid emergency response to find victims and treat the injured after the scale of the disaster became clear, said state secretary Pratikno, who like many Indonesians goes by only one name.
As many as 10 trapped people were rescued from areas surrounding Lumajang, according to Muhari, as villagers and rescuers worked through the night to find anyone trapped or retrieve bodies.
Local broadcaster Kompas TV reported those rescued were local workers at a sand mining site.
Evacuations were temporarily suspended on Sunday due to hot ash clouds, Indonesia’s Metro TV reported, highlighting the difficulty of the rescue operation.
There is also a risk of heavy rain causing ash sediment to form a new river of hot lava, the country’s top volcanologist Surono told the station.
Most of those burnt in the immediate aftermath misunderstood the size of the eruption and subsequent lava flow so had stayed in their villages, Lumajang Public Order Agency spokesman Adi Hendro told AFP.
“They did not have time to run away,” he said.
At least seven people remain missing after the eruption, Hendro said, including two who authorities believe are still alive.
“There were signs they are still alive as there were lights maybe from their cellphones,” he said.
“But we cannot go there as the ground is still very hot. We want to ensure our team’s safety too.”
Lava mixed with debris and heavy rain had already destroyed at least one bridge in Lumajang, preventing rescuers from immediately accessing the area.
But emergency services footage on Sunday showed a desolate scene in the village of Kebon Renteng swallowed by the eruption, with roofs of houses protruding from a coat of mud that destroyed them.
Rescue workers dressed in bright orange uniforms worked against a dark-grey backdrop in the village of about 11,000, now a scene of ruin with buckled buildings and fallen trees.
In other areas, distressed villagers desperately tried to salvage their belongings from wrecked homes. Some held mattresses and furniture on their shoulders while others carried goats alive in their arms.
The rescue teams were using heavy loaders to remove debris and clear roads, Muhari said.
Locals have been advised not to travel within five kilometres (3.1 miles) of Semeru’s crater, as the air around it is highly polluted and could affect vulnerable groups, he added.
“For now, we urge people not to stay because the volcanic ash is still relatively hot,” Indra Wibowo, head of the local disaster agency, told Metro TV.
Officials have sent aid to shelters, including food, tarpaulins, face masks, and body bags.
Ash spewed by the volcano travelled up to four kilometres away, Indonesia’s geological agency said, reaching as far as the Indian Ocean in the southern part of Java.
But Australia’s Volcanic Ash Advisory Centre, which provides advice to the aviation industry, said the ash had now dissipated around Semeru on Sunday, according to satellite imagery.
The volcano’s alert status has remained at its second-highest level since its previous major eruption in December 2020, which also forced thousands to flee and left villages covered.
The head of Indonesia’s centre for volcanology said it had warned officials on Thursday about increased volcanic activity and said people in the region should be on alert.
Indonesia sits on the Pacific Ring of Fire, where the meeting of continental plates causes high volcanic and seismic activity.
The Southeast Asian archipelago nation has nearly 130 active volcanoes.
In late 2018, a volcano in the strait between Java and Sumatra islands erupted, causing an underwater landslide and tsunami which killed more than 400 people.