TAIPEI (Taiwan News) — A new barrier lake was discovered on Tuesday, about 300 meters downstream from an existing one on the Mataian Creek in Hualien County, prompting authorities to maintain a red evacuation alert for residents in three townships.

The alert, initially issued in response to Tropical Storm Fung-wong and affecting around 5,000 residents, was originally set to be lifted at 7 a.m. Tuesday. However, it will remain in place following the discovery of the newly formed landslide dam, according to the Forestry and Nature Conservation Agency, per UDN.

Drone footage captured by FANCA showed the barrier lake forming after a landslide blocked the creek. The agency said it is assessing the potential water volume and overflow rate and has notified downstream workers to evacuate their equipment.

Huang Chun-tse (黃群策), head of FANCA’s Hualien Office, said follow-up drone photography revealed that the right bank’s earthen embankment had become unstable and collapsed. The extent of flooding, lake size, dam height, and overall impact are still being evaluated, he added.

The previous barrier lake on the Mataian Creek formed in late July and overflowed on Sept. 23. Another lake formed downstream on Oct. 21 but breached the same day.

Forestry officials said the earlier barrier lake’s water volume had decreased by about two-thirds to roughly 600,000 tonnes, covering 7.8 hectares. However, the new lake poses renewed risks, and the red alert will continue for residents of Wanrong, Fenglin, and Guangfu Townships.