A landslide-formed lake on the Wanli River in Hualien, Taiwan suddenly cut through its natural dam overnight, releasing a huge surge of water downstream — dangerous for anyone near the river, though the worst case has so far been avoided.

• Heavy overnight rain pushed the lake to near-record levels, then the dam began eroding at about 1 a.m. and the water level fell 4.7 meters in four hours.
• Roughly a million tons of water flowed out, though the erosion eased by morning and levels have steadied.
• A red alert stays in force inside the riverbed — no entry allowed — covering waterworks, a water treatment plant, and rail and highway bridges over the Wanli River.
• A yellow alert covers villages in Wanrong Township and Fenglin Town, where officials are moving out elderly and disabled residents first and readying shelters.
• Rainfall forecasts have been revised down sharply from earlier alarming numbers, easing fears of another rapid rise.

Outlook: Rain is expected to taper off by evening, but the riverbed stays closed while officials watch for further collapse of the natural dam.