Central South Korea faces extreme heavy rainfall of up to 80 mm per hour starting early Saturday morning [1].

The forecast warns of significant danger to infrastructure and residents, as such intense precipitation levels frequently trigger sudden flooding and landslides in mountainous or urban areas [3].

Weather officials expect the heaviest rain to hit southern Gyeonggi, southern Gangwon, and northern Chungnam provinces from early morning to mid-morning on July 18 [1, 2, 3]. The extreme weather is driven by a re-intensifying stationary front and a developing low-pressure system [2, 3].

Recent activity already indicates the severity of the current weather pattern. In Boryeong, Chungnam, rain reached 30 mm per hour around 6:30 a.m. on Friday following the issuance of a heavy rain advisory [1].

Daily maximums for Friday vary by region. Forecasts indicate up to 80 mm in Honam and Yeongnam, while Chungcheong may see up to 60 mm [2]. Other reports suggest maximums of 60 mm in Chungcheong and Gyeongnam, with 50 mm in Honam and Gyeongbuk [1].

"Extreme heavy rain of more than 80 mm per hour is falling, and there are concerns that flood and landslide damage may increase," Jung Hye-yoon said [3].

Local authorities are monitoring the stationary front as it strengthens. The timing of the peak intensity is critical for emergency services, as the window between the onset of the rain and potential flash flooding is narrow during "extreme rainfall" events [1, 2].

"Heavy rain will pour down on the central region from tomorrow's dawn until morning," a YTN anchor said [2].

“Extreme heavy rain of more than 80 mm per hour is falling”

The convergence of a stationary front and a low-pressure system creates a high-risk scenario for South Korea's central provinces. When rainfall exceeds 80 mm per hour, drainage systems are often overwhelmed, transforming streets into rivers and destabilizing soil on slopes. This specific meteorological combination suggests a concentrated burst of water rather than a steady rain, which significantly increases the likelihood of casualties and property destruction in high-risk zones.