The Meteorology, Climatology and Geophysics Agency (BMKG) forecast more anomalous torrential rain, thunderstorms and strong winds in most parts of the country, including Java and Sulawesi, in the coming days until Thursday, during the peak of what is normally the dry season.

The unusual heavy rain has been caused by the Madden-Julian Oscillation intraseasonal tropical climate variability, coupled with equatorial Kelvin and Rossby waves and warmer sea surface temperatures in waters around Indonesia that cause more clouds to build up in parts of the country, the weather agency said.

The Madden-Julian Oscillation is a sub-seasonal atmospheric phenomenon that influences tropical precipitation in an area. It moves eastward through the Indo-Pacific Ocean region and produces anomalous rainfall patterns.

“This atmospheric phenomenon triggers weather dynamics that result in downpours in most parts of Indonesia,” Guswanto, the deputy for meteorology at the BMKG, said in a press release recently.

Another BMKG official, Andri Ramdhani, warned people, particularly those living near rivers and in hilly areas, of possible flash floods and landslides after heavy rain.

At least 12 people died after a heavy downpour triggered a landslide in an illegal gold mine in Bone Bolango regency, Gorontalo, on Sunday, the latest in a string of hydrometeorological disasters that struck the country in the past week.