TANAH DATAR, Indonesia (AFP)— At least 34 people were killed and 16 more were missing in western Indonesia after flash floods and cold lava flow from one of the archipelago’s most active volcanos damaged homes, roads and mosques, officials said Sunday.

Hours of heavy rain caused flooding in Agam and Tanah Datar districts in West Sumatra province on Saturday evening, threatening thousands of people after the downpours swept ash and large rocks down Mount Marapi.

“I heard the thunder and the sound similar to boiling water. It was the sound of big rocks falling,” housewife Rina Devina told AFP, adding that three of her neighbours were killed.

“It was pitch black, so I used my cellphone as a flashlight. The road was muddy, so I chanted ‘God, have mercy!’ over and over again,” she said of her evacuation to a local official’s office.

West Sumatra disaster agency said 16 people died in Agam district and 18 in Tanah Datar, with 18 people injured overall.

“We are also still searching for 16 other people,” agency spokesman Ilham Wahab told AFP.

He said the search effort involved local rescuers, police, soldiers and volunteers.

Abdul Malik, head of the search and rescue agency in provincial capital Pandang, told reporters three more people had died but they were yet to be confirmed by other authorities.

The flash floods and cold lava flow hit the two districts at around 10:30 pm (1530 GMT) on Saturday, according to the Basarnas search and rescue agency.

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

Abdul Muhari, spokesman for the national disaster mitigation agency, or BNPB, said in a statement that 84 homes, 16 bridges and two mosques were damaged in Tanah Datar, as were 20 hectares (49.4 acres) of rice fields.

About 370,000 people live in the district, where several mosques and a public pool were also damaged, with large rocks and logs scattered on the ground, according to an AFP journalist at the scene.

In Lembah Anai, a popular tourist spot with a waterfall in Tanah Datar, a road connecting the cities of Padang and Bukittinggi was severely damaged and access for cars was cut off.

Aerial images seen by AFP of the district showed roads covered by mud, with roofs and a mosque’s minarets jutting out of the sea of brown mud.

Ilham said Sunday that authorities were still receiving reports of missing people from relatives.

He said he could not give a figure for the number of people evacuated from the area because the search and rescue effort was still focused on the victims and the missing.

Two trucks had been swept away by the flooding and strong currents in a nearby river in Tanah Datar, the journalist said.

In Agam, which has a population of more than 500,000 people, dozens of homes and public facilities were damaged, the district’s disaster agency chief Budi Perwira Negara told reporters.

He said 90 people had been evacuated to a school being used as a shelter.

Nine bodies, including those of a three-year-old and an eight-year-old, were identified on Sunday, Malik said in an earlier statement.

Authorities sent 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 areas of Agam and Tanah Datar.

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