The crisis began late Wednesday when intense rainfall pounded the reservoir’s upper catchment.
Inflows climbed so sharply that operators were forced to raise the discharge to 1,200 cu.m/s, a volume locals say they have not seen in years. Downstream floodwaters spilled into homes within hours, rising to 1–1.5 meters and turning neighborhoods into fast-moving brown lakes.
Lien Huong Commune officials had mobilized through the night, going door to door to evacuate families before the water reached its peak.
"If we hadn’t moved early, people would have been trapped," local authorities said.
At sunrise, the devastation was most visible at the Lien Huong river mouth. The torrent from upstream crashed into the anchorage where fishing boats are normally sheltered, sinking 13 vessels and tearing loose the anchors of 25 more. The freed boats drifted toward the open sea as fishermen looked on helplessly; the current was simply too strong for anyone to attempt a rescue.
Fishing boats anchored in the river were torn loose by floodwaters and swept out toward the estuary in Lam Dong Province, Dec. 4, 2025. Video by Long Huong
Along both banks of the Long Song river, more than 100 hectares of crops vanished under over 1.5 meters of water. Livestock were carried away by the current, and debris littered the fields. Early estimates put total losses at more than VND30 billion (US$1.1 million), but officials caution that the figure could rise as assessment teams reach more remote areas.
By midday, the reservoir's outflow had been reduced to 200 cu.m/s, and water levels were slowly retreating. Yet the flooding extended beyond Tuy Phong: prolonged rain and flood releases from the Song Luy and Song Quao irrigation systems also inundated parts of Bac Binh and Ham Thuan Bac districts, temporarily cutting off sections of National Highway 1.
Meteorologists warn that this is part of a larger rain pattern driven by a weakening Storm Koto. From southern Quang Tri to Da Nang and across eastern Quang Ngai, rainfall totals of 40–80 mm are expected over the next 24–48 hours, with pockets topping 120 mm. Central Highlands provinces and Vietnam’s southeastern region may also see heavy downpours, adding new risks to already saturated terrain.