Swapna Kumbar , Bengaluru - A heavy-rain landslide in Arunachal Pradesh’s Lower Siang district has blocked the Siji River, creating an artificial lake and raising fears of a sudden flash flood if the debris dam breaks. Authorities have warned people in Likabali and other downstream areas in Assam, where the river is known as the Gai, to stay alert and move to safer ground if needed.

District officials said the landslide struck at Siji-Magi Block Point after intense rainfall, choking the river’s flow and building up water behind the blockage. Because the dam is unstable, officials fear that a breach could send a fast-moving surge downstream, threatening homes, livestock, roads, bridges and other infrastructure. The area sits a few miles above Likabali town on the Arunachal-Assam border, making communities in both states vulnerable if the water suddenly releases.

Local authorities have advised residents to avoid riverbanks, limit travel near flood-prone stretches and evacuate low-lying areas if instructed. People have also been told to report unusual rises in water level, strange noises or signs that the blockage is weakening. The alert comes as Arunachal Pradesh continues to reel under heavy rain, landslides and flash floods that have already disrupted transport and added to the risk across the region.

For now, the main concern is not the blocked river itself but the danger of an abrupt release if the natural dam fails. Downstream Assam is watching closely, with officials urging residents to remain prepared until the situation stabilizes.