Local authorities in Hualien County, Taiwan, issued evacuation warnings after a newly formed barrier lake in the mountains threatened to overflow [1, 2].
The situation poses a critical risk to downstream townships, where a sudden breach of the natural dam could trigger flash flooding. This emergency coincides with the approach of Typhoon Mekkhala, which increases the likelihood of further heavy rainfall [2].
Officials discovered the barrier lake over the weekend [1, 2]. The lake formed when a landslide, triggered by heavy rain and the approaching typhoon, blocked a river in the mountains of Hualien County on Taiwan’s east coast [2]. This natural blockage has trapped a significant volume of water, creating a precarious reservoir above residential areas [1, 2].
Authorities said an overflow could occur in the coming days [1, 2]. To mitigate the risk to human life, local officials have begun drafting evacuation plans, and alerting residents in the affected downstream townships [1, 2].
The geography of Hualien's east coast makes it particularly susceptible to such events. The combination of steep terrain and intense tropical weather often leads to landslides that obstruct waterways, creating temporary lakes that can fail without warning [2].
Emergency teams continue to monitor the water levels and the stability of the landslide debris. Officials said they are prioritizing the safety of the population as the storm system moves closer to the region [1, 2].
“A newly formed barrier lake in the mountains of Hualien is at risk of overflowing”
The formation of a barrier lake during a typhoon creates a compounding disaster scenario. While the storm brings immediate wind and rain threats, the landslide-induced dam creates a secondary, unpredictable hazard that can cause catastrophic flooding even after the primary weather system has passed, necessitating high-alert evacuation protocols for mountainous regions.
