At least four people have died, and several others were rescued as intense monsoon rains battered central and southern parts of South Korea, lashing it with the most rainfall in 120 years.
Authorities issued their highest-level landslide alert on Thursday, adding that the next 48 hours will be critical as rainfall totals rise and saturated ground increases the likelihood of flash floods and slope collapses.
In Seosan, South Chungcheong Province, a man in his 50s died after his car was swept away in floodwaters. According to local reports, he called his wife in the early hours of Thursday and said: “The car is being swept away.”
Emergency crews found the submerged vehicle around 6.15am and rushed him to Seosan Medical Centre, where he was pronounced dead. Authorities had received a report about sunken vehicles at 3.59am and rescued three people from another car just an hour earlier.
Police are investigating the incident, which occurred as rainfall in Seosan peaked at 114.9mm per hour, the highest rate since records began in 1904, Yonhap reported.
Two men in their 80s were also killed in flood-related situations, including one who was believed to be trying to drain floodwaters from the basement of his home, authorities said.
At least 1,300 people have been asked to evacuate. including residents of Hongseong County, also in South Chungcheong, due to flooding from a nearby stream. Several schools and nurseries were closed as a precaution, authorities said.
Heavy rain triggered a landslide in Cheongyang, leaving two residents briefly trapped before being rescued. Over 100 residents were forced to leave their homes, according to the Yonhap Agency.
More than 400mm of rain has already fallen in parts of South Chungcheong Province since Wednesday. On Thursday, the Korea Forest Service raised the landslide risk to its highest “serious” level in central regions, including South and North Chungcheong provinces, as well as parts of Gyeonggi Province.
The national disaster agency also raised its emergency response to Stage 2, which allows for stronger coordination between national and local authorities and the mobilisation of more personnel and resources.
In Gwangju, where 426mm of rainfall was recorded on Thursday, residents said they have never seen anything like this ever before.
“I’ve never seen a flood here before, since there is no stream or river in this neighbourhood,” Ms Kim, a 26-year-old cafe owner told BBC.
The Korea Meteorological Administration (KMA) warned that up to 300mm of additional rain could fall by Saturday in some of the hardest-hit areas, with sudden downpours reaching 80mm per hour likely. Localised hourly rainfall has already exceeded that threshold in places, overwhelming drainage systems and triggering disaster alerts.
The erratic rainfall pattern is linked to the collision of a descending cold air mass from the northwest with warm, moist southwesterly winds from the North Pacific. This has created a large and unstable rain cloud system over the Yellow Sea, fuelling intense rainfall across the country.
In Osan, Gyeonggi Province, a 10m retaining wall collapsed during heavy rain on Wednesday, crushing two vehicles and killing a man in his 40s. Another man in his 50s escaped after only part of his car was buried. Fire officials also responded to a flooded underpass in Dangjin, South Chungcheong, as rainfall inundated roads and damaged property across the region.
As of Thursday, at least 29 streams and four riverside parking lots were closed in the Seoul metropolitan area, including Cheonggyecheon and Anyangcheon, as flood warnings remained in effect. Train services on the Gyeongbu, Janghang, and Seohae lines were also partially suspended due to waterlogged tracks.
Forecasts show that southern Gyeonggi could receive up to 80mm of rain per hour through Thursday night, with Seoul, Incheon and northern Gyeonggi expected to see 30–50mm per hour. South Chungcheong could see similar levels into early Friday, while rainfall in Gangwon may peak at 50mm per hour.
Other areas under watch include North Jeolla, Gwangju, South Jeolla, Busan, Ulsan, South Gyeongsang and Jeju Island, where rainfall could range from 30 to 80mm per hour depending on the region. Although the monsoon has officially ended in southern regions and Jeju, the scale of the low-pressure system is allowing rain bands to extend across the entire country.
The saturated soil is increasing the risk of landslides even in areas receiving relatively modest rainfall. The KMA has advised residents to avoid underground roads, streams and flood-prone zones, especially in the early morning and overnight hours when visibility is low. Evacuation plans are being advised for those living near vulnerable slopes or riversides.
