Indonesian Government Investigates Sumatra Natural Disasters

Causes of Floods and Landslides Identified

The Indonesian Ministry of Energy and Mineral Resources (ESDM) through its Geological Agency has conducted an investigation into the recent floods and landslides that have affected multiple regions in Sumatra. The agency's Acting Head, Lana Saria, reported that the disasters in five regencies - Humbang Hasudutan, Agam, Mandailing Natal, Gayo Lues, and Southeast Aceh - were triggered by three primary factors.

1. High to extreme rainfall was identified as the dominant factor
2. Steep to very steep geomorphology contributed to the vulnerability of the areas
3. Weathered lithology prone to erosion further exacerbated the situation

Government Response and Prevention Strategies

The government has expressed deep condolences for the victims and is currently focusing on emergency response and recovery efforts for the affected communities. In addition to immediate relief, the ministry is developing long-term prevention strategies. These include:

• Community capacity building through identification of early landslide signs and evacuation routes
• Revitalization of slope vegetation to enhance stability
• Land use control on steep slopes, including limitations on new land clearing
• Improvement of surface drainage to reduce risk in residential areas

Regional Vulnerability Assessment

The Geological Agency's analysis revealed that areas affected by landslides in two North Sumatra regencies are generally located in hilly to very steep terrain surrounding Sibolga City, particularly on the southeast side. According to the agency's Land Movement Vulnerability Zone Map, Sibolga City is classified as having medium to high potential for land movement, indicating that the area can and often experiences such events.

The Meteorology, Climatology, and Geophysics Agency (BMKG) also provided additional context, analyzing the development of Tropical Cyclone Seed 95B which was first identified on November 21, 2025, in the eastern waters of Aceh and the Malacca Strait. This weather system contributed to the extreme rainfall that triggered the disasters.