Jakarta. The Disaster Mitigation Agency (BPBD) of Jakarta has launched a five-day weather-modification operation, dispersing sea salt (sodium chloride, NaCl) from aircraft over the waters south of Banten through to Sukabumi in West Java in an effort to prevent high-intensity rainfall in the greater Jakarta area. On the final day of the operation, Sunday, the agency deployed approximately 1.6 tons of salt.

“We conducted two flight missions focused on spreading salt over the waters south of Banten to the south of Sukabumi,” said BPBD Jakarta head Isnawa Adji. He explained that the operation aims to reduce the risk of flooding by disrupting the growth of major rain-bearing clouds before they enter Jakarta.

During Sunday’s mission, the flight team observed cumulus humilis clouds forming near Halimun National Park at altitudes of 6,000–7,000 feet, and stratus/stratocumulus clouds in the target seeding area at 9,500–10,000 feet. Over the waters south of Sukabumi, cumulus and stratocumulus clouds were recorded with peaks above 14,000 feet. A separate sortie over the waters south of Banten encountered cumulus congestus clouds with tops reaching 12,000–14,000 feet.

The mission is being conducted in collaboration with the Meteorology, Climatology, and Geophysics Agency (BMKG) and the Indonesian Air Force. “We ensure each flight mission delivers significant results in controlling the potential for extreme weather. With this step, we hope flood and pooling risks in Jakarta can be suppressed,” Isnawa said.

Weather-modification -- often referred to as cloud-seeding or weather engineering -- is the practice of altering local weather conditions, usually temporarily, to reduce or shift precipitation (rain) intensity. The goal is not to change the climate, but to intervene in immediate weather systems. 

In a cloud seeding operation, aircraft spread hygroscopic salts into clouds. The salt particles act as nuclei for condensation, accelerating droplet formation and precipitation, or altering cloud dynamics to disperse moisture before it falls in a vulnerable area. 

While cloud-seeding has been used in Indonesia repeatedly, it is not a guaranteed solution. Analysts note it depends heavily on cloud type, humidity conditions, and atmospheric stability.