Situation Report #6 - Floods and Landslides in Aceh Province, North Sumatra, and West Sumatra - Thursday, 4 December 2025

Situation Report VI : FLOODS AND LANDSLIDES - ACEH, NORTH SUMATRA, AND WEST SUMATRA 2025

Key Information

1. The floods and landslides that struck 3 provinces and 52 districts or cities have damaged more than 156,500 houses and displaced 900,000 people.
2. Although floodwaters have begun to recede in several areas, most residents remain unable to return home due to mud and sediment from flash floods reaching depths of up to 2 meters has been filling their houses.
3. As of Monday (8 December 2025), the total number of deaths caused by the floods and landslides has risen to 950 people, with 274 missing and more than 5,000 injured.
4. Access to several affected locations, including Aceh Tamiang, Central Aceh, Gayo Lues, Langkat, Sibolga, and South Tapanuli, had previously been completely cut off. Access was gradually restored via air routes, and land routes have now begun to reopen.

Situation Overview

The floods and landslides that struck the Sumatra region in late November 2025 have caused severe and widespread impacts. The disaster resulted from several interconnected factors. Extreme rainfall was the primary trigger, with northern Sumatra experiencing continuous heavy rain for several days. According to the Meteorology, Climatology, and Geophysics Agency (BMKG), rainfall in certain areas reached over 300 millimeters in a single day. Atmospheric conditions such as Tropical Cyclone Senyar, which formed in the Malacca Strait, further intensified rainfall. Recorded wind speeds reached 80 km/h, strengthening moisture flow into the region. Environmental degradation caused by land-use change significantly worsened the flooding. The Deputy Minister of Public Works explained that reduced vegetation cover lowers the soil’s ability to absorb water, causing rainwater to flow rapidly into rivers and trigger flooding.

According to data from the National Disaster Management Agency (BNPB), retrieved from its official dashboard as of 8 December 2025 at 13:00 WIB, the disaster has resulted in 950 deaths, 274 missing, over 5,000 injured, and 900,000 displaced. Infrastructure damage is extensive and includes 156,500 houses, 1,200 public facilities, 199 health facilities, 534 educational facilities, 420 houses of worship, 234 office buildings, 435 damaged bridges. These conditions have not only caused significant loss of property and shelter but have also severely disrupted education, healthcare access, community mobility, and local economic activities. BNPB warns that these numbers may continue to increase as many affected areas remain inaccessible.

The Human Initiative Emergency Response Team has been actively coordinating with local volunteers, BPBD, and local authorities. Emergency actions and humanitarian aid have been delivered across the three affected provinces: Aceh, North Sumatra, and West Sumatra.