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Assam has sounded a flood alert after flash floods triggered by intense rainfall in Arunachal Pradesh's Lower Subansiri district led to a sharp rise in river discharge, raising concerns of downstream impacts across several districts over the next 24 to 48 hours.

According to official information, Yazali in Lower Subansiri recorded 72.8 mm of rainfall in the past 24 hours, with the heaviest downpour occurring between 6 am and 9 am on June 24. Meteorological assessments indicated torrential rainfall between 6 am and 7.30 am, resulting in flash floods and a sudden increase in water flow in the upper catchment areas.

The flash floods affected the Panyor Lower Hydroelectric Project area, formerly known as the Ranganadi Hydroelectric Project. Authorities opened one spillway gate to release excess water following a sharp rise in inflows. Reports from Yazali also indicated damage to houses and infrastructure due to floodwaters and debris flow.

Officials warned that increased river discharge from the upper catchments is likely to cause a significant rise in water levels and flow velocity in the Brahmaputra and its tributaries in Assam. The flood wave is expected to first impact Dhemaji, Lakhimpur, Biswanath and Sonitpur districts before moving further downstream towards Dhubri.

The Assam government has directed district administrations and line departments in vulnerable districts to remain on high alert and undertake preparedness measures. Emergency response teams, including the State Disaster Response Force (SDRF) and National Disaster Response Force (NDRF), have been kept ready for deployment.

Residents of low-lying and flood-prone areas have been advised to remain vigilant and follow instructions issued by local authorities. People have also been cautioned against entering inundated areas or travelling by small boats as river currents are expected to strengthen considerably.