Jakarta.  Indonesia’s Meteorology, Climatology, and Geophysics Agency (BMKG) warned of potential extreme weather during the 2024 Christmas and 2025 New Year holidays due to a Siberian cold surge. The phenomenon could trigger heavy rainfall and hydrometeorological disasters, including flooding, particularly in western Indonesia.

BMKG Chief Dwikorita Karnawati, speaking to Commission V of the House of Representatives on Wednesday, said the areas most at risk include West Java, Jakarta, Banten, and Lampung.

“If the Siberian cold surge reaches western Indonesia, it could lead to extreme rainfall. We hope the worst-case scenario does not occur,” she said.

The Siberian cold surge occurs when cold air from the Siberian-Mongolian High (SMH) moves southward, increasing atmospheric pressure and intensifying northerly winds that extend as far as the equator. This phenomenon often interacts with convection processes over the South China Sea and the Java Sea, causing severe weather and disrupting agricultural and economic activities.

BMKG forecasts that the cold surge could begin affecting Indonesia as early as Dec. 20, with its peak impact expected between Dec. 20 and Dec. 29. “The surge is projected to intensify rainfall and wind speeds during the Christmas week,” Dwikorita noted.

She also drew parallels to the devastating flooding in Greater Jakarta in January 2020, caused by a similar cold surge. “We witnessed severe flooding in early 2020 due to a Siberian cold surge. Similar conditions could potentially occur again,” she warned.

The weather agency also cautioned about maritime risks, including rough seas and strong winds, which could disrupt transportation and port operations. Dwikorita recalled a past incident at Merak Port in Banten, where strong winds caused a docked ship to tilt, sending vehicles into the sea.

“These incidents underline the serious risks posed by cold surges,” she said, urging transportation authorities, maritime operators, and local governments to prepare for potential disruptions.

BMKG is closely monitoring the situation and will issue updates to inform the public and relevant authorities of any emerging risks. “Enhanced preparedness and continuous monitoring are essential to minimize the impact on communities,” Dwikorita concluded.

The agency called for vigilance, particularly in vulnerable regions like the Sunda Strait, Banten, Lampung, West Java, and Central Java, urging all parties to coordinate efforts to ensure public safety.