The Meteorology, Climatology and Geophysics Agency (BMKG) reports that the extreme weather affecting several regions of North Sumatra over the past week is linked to Tropical Cyclone Senyar.
Head of BMKG Region I, Hendro Nugroho, stated that Senyar originated from tropical cyclone seed 95B which developed in the Malacca Strait on 21 November 2025.
“Over the past week, North Sumatra has experienced daily rainfall,” Hendro said.
BMKG recorded heavy to extreme rainfall with long durations across multiple monitoring stations.
The highest intensity was observed at ARG Pakkat at 238.4 mm on 25 November, followed by Stamet F.L. Tobing at 229.7 mm on 24 November. Stations in Tapanuli, Hapesong, Teluk Dalam, Asahan, Salak and Hinai Langkat also reported high levels of rainfall.
BMKG said humidity remained very high, supporting the potential for heavy to very heavy rain. The negative Indian Ocean Dipole (IOD) phase, which increases moisture from the west coast, is expected to persist until December.
Active atmospheric waves continue to add moisture over North Sumatra. Hendro noted that heavy rain remains likely in Langkat, Medan, Binjai, Deli Serdang, Karo, Dairi, Pakpak Bharat, Tapanuli Tengah, Sibolga, Tapanuli Selatan, Padang Sidempuan, Tapanuli Utara, Mandailing Natal, Padang Lawas, Padang Lawas Utara, Simalungun, Samosir, Serdang Bedagai, Tebing Tinggi, Humbang Hasundutan, Nias, Nias Selatan, Nias Utara, Nias Barat, Gunungsitoli and Toba.
“Meteorological conditions are dynamic. We urge the public to monitor BMKG’s updates. Regional leaders should coordinate with BPBD, the TNI and the police,” Hendro said, as quoted by Antara.
@channelnewsasia At least 17 are dead after torrential rains unleashed flash floods and triggered landslides on Indonesia’s Sumatra island, authorities said on Wednesday (Nov 26). Rescue teams are struggling to reach affected areas in six regencies of North Sumatra province after the monsoon rains over the past week caused rivers to burst their banks. More than 2,000 residents are said to have been displaced since the floods hit the region. #indonesia #indonesianews ♬ original sound – CNA
Casualties Rise as Floods and Landslides Spread Across the Province
The North Sumatra Disaster Management Agency (BPBD) reports that nine regencies and cities have been affected by floods and landslides as of Wednesday.
Emergency Response Head Yuyun Karseno said access routes in Tapanuli Tengah, Tapanuli Selatan and Sibolga were disrupted by hydrometeorological hazards.
According to BPBD North Sumatra, 24 people have died, five remain missing and 58 were injured.
In Tapanuli Selatan, the regional BPBD confirmed 15 fatalities. The victims include one resident of Sipirok, one from Angkola Barat, and 13 from Batangtoru. Around 3,000 households have been displaced after heavy rainfall on 24 November caused rivers to overflow and triggered slope failures in several areas.
BPBD Chief Executive Zulkarnaen Siregar said teams continue to evacuate residents and assess damage.
“Rainfall remains high, so evacuations are carried out with caution. Several points are still submerged and some areas remain difficult to reach,” he said on Wednesday, as reported by Tempo.
The Tapanuli Selatan government has declared a 14-day emergency response period starting 25 November. Immediate needs include food packages, family kits, kitchen kits, tents, mattresses, blankets and rubber boats. Responders also require chainsaws and cleaning equipment.
The National Disaster Management Agency (BNPB) urged residents to remain vigilant, noting unstable weather in the highland areas of Tapanuli Selatan.
International Media Coverage
International media also reported on the disaster. Associated Press (AP) stated heavy rainfall triggered floods and landslides across hillside villages in North Sumatra, causing casualties and hampering rescue operations due to damaged access routes.
In Sibolga, AP reported at least five fatalities and ongoing searches for missing residents. Landslides in Tapanuli Tengah destroyed several homes and killed a family of four, while nearly 2,000 houses were flooded. AP also noted incidents of fallen trees causing casualties in Tapanuli Selatan and damage to homes and infrastructure in Mandailing Natal.
Agence France-Presse (AFP) reported at least eight deaths in Tapanuli Selatan, with 58 people injured and more than 2,800 residents displaced. BNPB official Abdul Muhari said heavy machinery had been deployed to clear landslide debris blocking roads.
AFP noted that several regencies in North Sumatra experienced similar impacts and highlighted BMKG’s explanation of the extreme weather pattern.
Environmental group WALHI called on the government to evaluate mining permits in Batang Toru, citing the increased disaster risk in the region.
