BMKG: Atmospheric Dynamics and Human Factors Trigger Floods During Dry Season

The Meteorology, Climatology, and Geophysics Agency (BMKG) has revealed that complex atmospheric dynamics and human interference are the primary triggers for flood disasters during the 2026 national dry season. Phenomena such as equatorial Rossby waves and environmental damage mean the potential for heavy rain still lurks even though some regions have entered the dry period.

BMKG Head Teuku Faisal Fathani explained that weather conditions during the transition to the dry season are currently heavily influenced by daily variations. “There are also factors related to equatorial Rossby waves, Kelvin waves, the MJO (Madden-Julian Oscillation), and so on that can cause daily variations,” Fathani said, as reported by Antara on Thursday (4/6).

Based on BMKG data up to the end of May 2026, only about 24 percent of the total 699 Seasonal Zones (ZOM) in Indonesia have officially entered the dry season. The rest are predicted to follow suit in June. Fathani added that the El Niño phenomenon, which emerged from April to May 2026, is expected to strengthen from weak to moderate in the third quarter of this year, particularly from August to October.

Besides natural factors, BMKG highlighted the significant role of humans in exacerbating disaster risk. Massive housing development, land conversion, and river siltation have made regions more vulnerable. As a result, moderate-intensity rainfall that was once considered normal can now instantly trigger flash floods and landslides.

This anomalous condition creates a dual challenge for disaster management in Indonesia. While several regions such as North Sulawesi struggle to cope with flooding, other areas on the island of Sumatra and West Nusa Tenggara are beginning to face an increased risk of forest and land fires due to a drastic drop in rainfall.