Heavy rain triggers a flash flood and a cold lava flow from Mount Marapi, resulting in the disaster in West Sumatra.

Basarnas search and rescue agency said in a statement on Sunday the disaster hit Agam and Tanah Datar districts in the West Sumatra province at about 10:30pm (15:30 GMT) on Saturday after hours of heavy rain, triggering a flash flood and a cold lava flow from Mount Marapi.

Cold lava, also known as lahar, is volcanic material like ash, sand and pebbles carried down a volcano’s slopes by rain.

Ilham Wahab, head of the Regional Disaster Mitigation Agency in West Sumatra, was quoted by the Indonesian media company, Sumbar, as saying that as of Sunday morning, at least 14 people had been reported killed.

Abdul Malik, head of the local rescue agency, said nine bodies were identified, including those of a three-year-old and an eight-year-old.

Four other people are still being searched in Agam district, he said. “Today, we will continue the search in the two districts.”

Photos and videos posted on social media showed large rocks and thick mud covering the streets of West Sumatra.

The disaster comes just two months after another deadly flooding hit the same island.

Authorities dispatched a team of rescuers and rubber boats to look for the missing victims and to transport people to shelters.

The local government set up evacuation centres and emergency posts in several spots in the two districts.

Indonesia is prone to landslides and floods during the rainy season.

Last week, 15 people were killed in South Sulawesi after landslides and flooding swept away homes and damaged roads.

In March, at least 26 people had been found dead after landslides and floods hit West Sumatra.

Saturday’s floods in Agam and Tanah Datar also carried cold lava down from Mount Marapi, the most active volcano in Sumatra and one of nearly 130 active volcanoes in the Indonesian archipelago.

In December, Marapi erupted and spewed an ash tower 3,000 metres (9,800 feet) into the sky, higher than the volcano itself.

At least 24 climbers, most of them university students, died in the eruption.

In a separate deadly incident on Saturday evening, at least 11 people were killed and dozens of others were injured when a bus carrying more than 60 high school students on a graduation trip and their teachers crashed on Indonesia’s biggest island of Java.