Heavy rains from Tropical Storm Mekkhala caused several deaths and forced the evacuation of more than 200 people in eastern Taiwan [1, 2].

The disaster underscores the vulnerability of Taiwan's mountainous coastlines to rapid flooding and the instability of barrier lakes during the typhoon season.

Emergency crews focused their efforts on Hualien County on the east coast, where authorities ordered residents to leave their homes [1]. The evacuations were triggered by the risk of a barrier lake overflowing, a condition that can lead to sudden and catastrophic flash floods in the valleys below [1].

While the most critical evacuations occurred in Hualien, the storm's impact extended to various communities in southern Taiwan [2]. The sustained precipitation from the tropical storm saturated the soil, increasing the risk of landslides, and urban flooding across these regions [2].

Local officials said several people died as a result of the weather conditions [2]. Recovery teams have been working to clear debris and assess damage to infrastructure in the affected small towns [2].

The events took place on June 25, 2024 [1]. Tropical Storm Mekkhala, acting as a nearby typhoon system, drove the moisture-laden air into the island's rugged terrain, which intensified the rainfall through orographic lifting [1, 2].

Authorities said they continue to monitor water levels in the barrier lake to determine when it is safe for the displaced residents to return to their homes [1].

“More than 200 people were evacuated in Hualien County.”

The overflow risk of barrier lakes, natural dams formed by landslide debris, represents a significant geological hazard in Taiwan. When tropical storms like Mekkhala provide sustained rainfall, these temporary dams can fail, creating a cascade of flooding that threatens downstream settlements. This event highlights the ongoing need for advanced early-warning systems in Hualien County to mitigate the loss of life during extreme weather events.