BMKG Alerts Fishermen to High Waves in North Sumatra Waters Until 15 March 2026

The Indonesian Agency for Meteorology, Climatology and Geophysics (BMKG) has warned fishermen and other stakeholders to remain vigilant regarding the potential occurrence of high waves in several North Sumatra waters that could disrupt shipping.

“Exercise caution with the potential for high waves from 13 to 15 March 2026. Sea waves may reach 1.5 to 2.5 metres,” said Rizki Fadhillah Pratama Putra, a forecaster at the BMKG Class II Maritime Meteorology Station in Belawan, during a briefing in Medan on Thursday.

Wind patterns in the northern regions of Indonesia generally move from north-west to north-east with wind speeds ranging from 5 to 25 knots, whilst in the southern regions of Indonesia, winds generally move from south-west to north-west with speeds ranging from 8 to 30 knots.

Several maritime zones that are at risk of being battered by high waves include the waters west of the Nias Islands, the waters west of the Batu Islands, the waters of the Batu Islands, and the Indian Ocean west of the Nias Islands.

Boat operators are advised to exercise caution when wind speeds reach 15 knots and wave heights reach 1.25 metres, whilst barge operators should be cautious when wind speeds reach 16 knots and wave heights reach 1.5 metres.

Meanwhile, Putri Diana, a forecaster at the BMKG Regional I office in Medan, noted that several areas in North Sumatra are at risk of experiencing light to moderate rainfall on Friday (13 March). Light rainfall is expected Friday morning with potential impacts in the areas of North Tapanuli, North Labuhanbatu, Mandailing Natal, South Nias, North Nias, Padang Lawas, Padangsidimpuan, Labuhanbatu, South Labuhanbatu, Asahan and Batu Bara.

During daytime to evening hours, the weather is forecast to be overcast with potential light to moderate rainfall in the Langkat region and its surroundings.

For evening hours, weather across North Sumatra is generally expected to be overcast with potential light rainfall across most regions, whilst overnight conditions are forecast to be overcast with potential light rainfall in several areas.

“BMKG urges the public to remain vigilant regarding the potential for moderate-intensity rainfall in the western and eastern slopes of North Sumatra, which could trigger hydrometeorological disasters such as flooding and landslides,” she stated.