At least 248 people have now died and more than 100 people are missing following floods and landslides in Indonesia, which has also been hit by an earthquake.
Monsoon rains over the past week caused rivers to burst their banks in North Sumatra province.
The deluge tore through mountainside villages, swept away people and submerged thousands of houses and buildings, the National Disaster Management Agency said.
Rescue workers have been struggling to reach some areas cut off by damaged roads, and where communications lines have come down. Authorities fear the number of dead will increase further.
Relief aircraft have been delivering aid and supplies to the hard-hit district of Central Tapanuli in North Sumatra and others in the region.
The agency said West Sumatra’s Agam district had also been affected. Some 76 people have died in that province.
Pictures of the rescue efforts show workers trudging through waist-deep mud and areas filled with tree trunks and debris, searching for any victims potentially trapped.
In Aceh province, flooded roads meant authorities struggled to get tractors and other heavy equipment to hilly hamlets which were hit by mud and rocks in the heavy rainfall.
Hundreds of police officers, soldiers and residents dug through the debris with their bare hands and shovels as heavy rain hindered their efforts.
Meanwhile, a magnitude 6.3 earthquake hit Sumatra island near Aceh province on Thursday, the country’s geophysics agency said.
Torrential rain triggered flash flooding and landslides in Sumatra earlier in the week. Videos posted on social media showed water streaming down from rooftops as panicked residents scrambled to safety.
Feel the heat of the frontline with Alex Crawford, Stuart Ramsay and their teams as they take you to some of the world's Hotspots
Heavy seasonal rain from about October to March often causes flooding and landslides in Indonesia – an archipelago of more than 17,000 islands including Sumatra – where millions of people live in mountainous areas or near fertile floodplains.
Keep up with all the latest news from the UK and around the world by following Sky News
Last week, almost 1,000 people from three villages on Java were forced to flee to shelters after the eruption of Mount Semeru, the island’s highest volcano.
