Indonesian rescuers retrieved four more bodies after they resumed their search Wednesday for people missing after floods and landslides on Indonesia’s main island of Java, bringing the death toll to 21.

Waters from flooded rivers tore through nine villages in Pekalongan regency of Central Java province and landslides tumbled onto mountainside hamlets after the torrential rains Monday.

Videos and photos released by National Search and Rescue Agency showed workers digging desperately in villages where roads and green-terraced rice fields were transformed into murky brown mud and villages were covered by thick mud, rocks and uprooted trees.

National Disaster Management Agency spokesperson Abdul Muhari said flooding triggered a landslide that buried two houses and a cafe in the Petungkriyono resort area. The disasters all together destroyed 25 houses, a dam and three main bridges connecting villages in Pekalongan. At least 13 people injured and nearly 300 people were forced to flee to temporary government shelters.

The search and rescue operation that was hampered by bad weather, mudslides and rugged terrain was halted Tuesday afternoon due to heavy rain and thick fog that made devastated areas along the rivers dangerous to rescuers.

On Wednesday, they searched in rivers and the rubble of villages for bodies and, whenever possible, survivors in worst-hit Kasimpar village, said Budiono, who heads a local rescue office.

Scores of rescue personnel recovered three mud-caked bodies, including a 5-month old baby, as they searched a Petungkriyono area where tons of mud and rocks buried two houses and a café. Another body was pulled out from under a broken bridge near a river in Kasimpar village. Rescuers are still searching for five people reported missing.

Landslides and floods were also reported in many other provinces, Muhari said. On Monday, a landslide hit five houses in Denpasar on the tourist island of Bali, killing four people and leaving one missing.

Read: Search resumes after deadly flooding and landslides in Indonesia

Heavy seasonal rain from about October to March frequently causes flooding and landslides in Indonesia, an archipelago of 17,000 islands where millions of people live in mountainous areas or near fertile floodplains.

Landslides of earth, rock and debris can happen suddenly or slowly and can be caused by rain, erosion, or changes to the slope’s material. Rain adds weight to the slope, making it more unstable.

The slope’s steepness or erosion at the base can make landslides more likely. They can be caused by the movement of nearby bodies of water or vibrations from earthquakes, mining or traffic. The types and sizes of the rocks and soils can determine how much water land can absorb before weakening and collapsing.

Studies have found that landslides could become more frequent as climate change increases rainfall.