Geoje city in South Korea's South Gyeongsang Province recorded more than 900 mm of rain [1] over two days ending Monday.
The extreme weather event marks the strongest rainfall the region has seen since Typhoon Rosa in 2002. Meteorologists describe the storm as a rare atmospheric occurrence with a statistical return period of approximately once every 200 years [1].
Rainfall began during the night of Aug. 16 and continued into Aug. 17, impacting Geoje and nearby Tongyeong. The intensity of the storm reached a peak hourly rate of 124.5 mm [1]. This figure represents the fourth highest hourly rainfall ever recorded in South Korea [1].
Data shows that the rainfall remained extreme for several hours. Between 2 a.m. and 4 a.m., the city experienced hourly rainfall exceeding 110 mm for two consecutive hours [1].
Ju Seon-young, a forecaster for the Korea Meteorological Administration, said the daily precipitation and maximum hourly rainfall in Geoje broke existing records. Ju said the rain fell with a probability that occurs once every 200 years [1].
Local authorities reported that the volume of water overwhelmed infrastructure in the coastal city. The event follows a pattern of increasing extreme weather volatility in the region, though the scale of this specific storm is considered an outlier by historical standards.
“The strongest rainfall since Typhoon Rosa in 2002.”
The occurrence of a '200-year event' suggests that current urban drainage and flood prevention infrastructure in South Korea's southern coastal cities may be insufficient for new extremes in precipitation. When hourly rainfall reaches the top four highest records in national history, it indicates a shift in atmospheric intensity that exceeds historical planning models.
