BMKG Warns of Tidal Flooding Along West Nusa Tenggara Coast, September 26-30
Indonesia's meteorological agency BMKG has warned that coastal areas of West Nusa Tenggara (NTB) province—including parts of Lombok, Sumbawa, and Bima—face a risk of tidal flooding from September 26-30, 2026, with sea levels potentially reaching 1.9 meters due to the Harvest Moon. High waves of 2.5-4 meters are also expected in nearby straits and the Indian Ocean south of NTB.
Indonesia's Meteorological, Climatological, and Geophysical Agency (BMKG) has issued a warning about potential tidal flooding, known locally as "banjir rob," affecting coastal areas of West Nusa Tenggara (NTB) province from September 26 to 30, 2026.
According to a forecaster at the Zainuddin Abdul Madjid Meteorological Station in Mataram, peak high tide in West Lombok is expected between 11 PM and 1 AM local time, while in Bima it will occur between midnight and noon. Maximum tide height is projected to reach 1.9 meters.
Areas at risk include:
- Lombok Island: Ampenan, Sekarbela, Gerung, Lembar, Pemenang, Jerowaru, and Labuhan Lombok
- Sumbawa Island: Sumbawa and Labuhan Badas
- Bima region: Palibelo, Belo, Woha, Bolo, Lambu, Langgudu, Soromandi, Sape, Rasanae Barat, Hu'u, and Asakota
The phenomenon is linked to lunar gravitational forces, coinciding with the "Harvest Moon" full moon appearing on September 26-27. Peak full moon timing varies from 11:49 PM to 1:49 AM depending on the region.
BMKG also warned of waves reaching 2.5 to 4 meters in the southern Lombok Strait, southern Alas Strait, waters south of Sumbawa, and the Indian Ocean south of NTB. Residents near coastlines, riverbanks, and low-lying areas are urged to monitor official BMKG channels for updated weather and wave conditions.
While this warning applies to NTB province rather than Bali itself, it is highly relevant for tourists traveling to Lombok from Bali and for anyone using ferry or boat services between the two islands during this period.
Things to Consider
If traveling to coastal areas of Lombok or Sumbawa (such as Ampenan, Sekarbela, or Lembar), avoid low-lying beachfront areas during peak tide hours (11 PM-1 AM in West Lombok, midnight-noon in Bima) between September 26-30. Those using ferry or boat services between Bali and Lombok should check with operators or BMKG's official channels for cancellations or delays due to expected 2.5-4 meter waves. If staying at coastal hotels or villas, confirm evacuation routes in advance in case of tidal flooding.
Source: ANTARA News Bali