TANAH DATAR, MAY 16

Indonesian authorities seeded clouds on Wednesday, trying to prevent further rain and flash floods after deluges that hit Sumatra Island over the weekend left at least 67 people dead and another 20 missing.

Monsoon rains triggered a landslide of mud and cold lava from Mount Marapi, eventually causing rivers to breach their banks. The deluge tore through mountainside villages in four districts in West Sumatra province just before midnight on Saturday.

The floods swept away people and dozens of homes and submerged hundreds of houses and buildings, forcing more than 1,500 families to flee to temporary government shelters, according to National Disaster Management Agency spokesperson Abdul Muhari.

He said 67 bodies had been pulled from mud and rivers by Wednesday, mostly in the worst-hit Agam and Tanah Datar districts, while rescuers are searching for 20 people reported missing. About 44 villagers were injured.

Cloud seeding involves dispersing particles into clouds to create precipitation, thereby modifying the weather.

National Disaster Management Agency chief Suharyanto said the aim of Wednesday's action was to redirect the rain elsewhere and keep the search operation free of downpours, which could hamper the rescuers' progress.

Suharyanto, who goes by a single name like many Indonesians, said the emergency response will last until May 25. Authorities are evaluating which areas are no longer inhabitable and which residents need to be relocated 'from the danger zone.'

Suharyanto spoke during a visit to the devastated villages in hard-hit Tanah Datar district on Wednesday.

Indonesia's Meteorology, Climatology and Geophysics Agency head Dwikorita Karnawati has said that more rain was forecast for West Sumatra in the coming days, and that extreme rainfall could continue until next week.

Karnawati said an air force plane was sent up to shoot salt flares into the clouds on Wednesday to get the clouds to release water and break up before they reach the devastated areas in West Sumatra province. About 15 tons of salt have been prepared for the seeding operation, she said.

Muhari, the disaster agency spokesperson, said Indonesia's air force teamed up with the country's technology agency to carry out two rounds of cloud seeding Wednesday each using a ton of sodium chloride, or salt.

Rescue workers meanwhile combed through rivers and the rubble of devastated villages where roads were transformed into murky brown rivers and villages were left covered by thick mud, rocks, and uprooted trees.

Heavy rains cause frequent landslides and flash floods in Indonesia, an archipelago nation of more than 17,000 islands where millions of people live in mountainous areas or near floodplains.

Marapi has been active since an eruption late last year that killed 23 climbers. It is among more than 120 active volcanoes in Indonesia. The country is prone to seismic upheaval because of its location on the Pacific 'Ring of Fire,' an arc of volcanoes and fault lines encircling the Pacific Basin.