The Case of Floods and Landslides in Indonesia

There were floods and landslides in Indonesia throughout 2025, particularly at the end of year. Heavy and prolonged rainfall is the extreme climate as the causing factor. To solve the disaster risks, the Indonesian government is implementing the appropriate evacuation procedures, besides the other programs like monitoring, prediction, and early warning systems.

The Case of Floods and Landslides in Indonesia

A series of climate disasters has struck Indonesia since the beginning of the year until the end of 2025. These include floods and landslides that caused by heavy rain. Jakarta and its surrounding areas are potential to flooding. It is different with the highlands in Bogor that threatened by landslides.

Several areas in Central Java have also faced similar climate disasters, even since the beginning of the year. Three sub-districts in Kebumen were also affected by the overflowing Angke River. Many families were evacuated. The same case occurred in Wonosobo.

Floods and landslides struck Cilacap, Central Java, towards the end of the year. The various impacts were loss of life and several missing persons. The risks material includes damage to residential areas and road access. Meanwhile, a few days later, an extreme landslide occurred in Situkung, Pandanarum, Banjarnegara on November 16^th, 2025. The land remained unstable and actively shifting.

The Risk Factors

Each disaster has its own risk factors. Floods and landslides in Indonesia are climate disasters caused by heavy rain. Water volume increases because of heavy rain and then causing rivers, ponds, and reservoirs to overflow. Finally, floods occurred.

Water pressure within the soil also increases, causing mass movement. This shift is prone to cracking. If the cracks worsen, the land is threatened with landslides. The risk of landslides is greater in barren highlands.

The other factors that influence the severity of floods and landslides such as soil structure, the trees as buffers, and the extent of water catchment areas. This is why the risks vary.

The Role of Weather Modification in Evacuation

Floods and landslides need quick handling. So, the evacuation process must be increased in technique, coordination, and facility. Based on the fact, there is the coordination of BMKG (Meteorology, Climatology, and Geophysics Agency) and BNPB (National Disaster Management Agency) to conduct weather modification operations before starting an evacuation.

The modification will control the weather at the disaster site, so the evacuation is more effective. Initially, heavy rainfall will lessen, or even subside, thereby reducing the volume of water and the potential for further landslides.

The BMKG will handle the technical implementation of weather modification, while the BNPB will provide operational funding in the form of disaster management funds. The weather modification process involves the following steps.

1. Cloud Target Identification

The weather modification operation started with identifying target clouds. Before the evacuation, the BMKG monitors weather conditions in the disaster area and analyzes the potential of weather patterns.

The analysis results are used to identify suitable clouds for weather modification. These clouds are identified using radar and satellites. Clouds selected are those with high water vapor potential. Wind direction is also taken into account to determine the most effective location to divert rain from the disaster area.

2. Preparation

After successfully identifying the target cloud, the next step is preparation. The materials needed are the seeding materials, such as sodium chloride (NaCl), calcium oxide (CaO), silver iodide (AgI), and the determination of the seeding location. The location is a reservoir, river, or sea far from the disaster area and residential areas. Weather data and the target cloud are used as a reference.

3. Sowing of Materials

Once everything is ready, the team immediately begins seeding. The technique is spreading hygroscopic chemicals (NaCl, CaO, AgI) into the target cloud. The spreading process is carried out with the help of aircraft, drones, or ground-based spreaders. These materials attract water molecules and then cause condensation. So, the formation of raindrops in the specified locations can be accelerated.

4. Monitoring the Results

The final stage is monitoring the results of the modification process. Monitoring is conducted in real time to ensure the effectiveness of the intervention and the accuracy of the rainfall locations. Flood and landslide areas are also continuously monitored to ensure that rainfall in those areas is decreasing or none at all. After this, the evacuation process will be completed quickly.

The increases risks from floods and landslides in Indonesia can be prevented with effective handling. Coordination between the BMKG and other related institutions is important for keeping evacuations effective. This team also operates based on data. Otherwise, the intervention could worsen the weather in other areas.

In practice, evacuations require public notification. It can be realized through emergency messages containing evacuation information. Currently, an emergency sending machine based on SMS (Short Message Service) is available at smsbroadcaster.com. This machine can send information to mobile phones in real time, without depending on an internet signal. It also has a wide range, from 500 m to 2 km.