Extreme heavy rain hit the South Gyeongsang coast over the weekend, delivering more than 500 mm of rainfall in a single day [2].
The scale of the precipitation poses a severe risk of flash flooding and landslides in coastal regions, necessitating emergency alerts for residents.
The rainfall concentrated on the Gyeongnam coastal areas, specifically affecting Geoje, Gadeokdo, Tongyeong, and nearby islands [1, 2]. Yoo Da-hyun, a caster at the Korea Meteorological Administration, said rain clouds remained over the west coast of South Jeolla province early yesterday, pouring down extreme rainfall [1].
Meteorologists attribute the event to a strong low-level jet. This system formed between a western low-pressure system and an eastern high-pressure system, which lifted moist air that slammed into the coastline to produce localized extreme rainfall [1].
Emergency disaster messages are triggered when rainfall exceeds 100 mm per hour [1]. While rainfall exceeding 30 mm per hour is generally classified as heavy rain, the current levels in the region have far surpassed those benchmarks [1].
Forecasters warn that the weather event is not over. Many locations along the Gyeongnam coast are expected to receive an additional 250 mm of rain [1].
“More than 500 mm of rain fell in a single day”
The combination of a low-level jet and colliding pressure systems has created a 'stationary' rain effect, where massive volumes of water are dumped on specific coastal coordinates rather than moving across the peninsula. This pattern increases the likelihood of infrastructure failure and soil saturation in the Gyeongnam region.
