South Korea’s Ministry of Interior and Safety said three of the dead were trapped in a submerged basement floor. The ministry said nine others were injured and at least seven were still missing.
Since midnight Monday local time, parts of Seoul have seen a total of 422 mm (16.6 inches) of rain, prompting authorities to raise the emergency alert level above level 3. The city recorded 141.5 mm (5.6 inches) of rain per hour – the highest Rate since authorities began keeping records.
Additional rounds of heavy rain are expected to move through Seoul through Thursday, potentially bringing additional flooding to the area.
Heavy rain warnings are in effect for the capital region and Gangwon-do, where 50 to 100 mm (2-4 inches) of rain is likely per hour, according to the Korea Meteorological Administration.
Images from around the city during flash floods on Monday show people wading through roads up to their thighs into the water.
Although the floodwaters had largely receded by Tuesday morning, cars and buses were left strewn across roads and sidewalks, blocking morning traffic.
In some parts of Seoul, drains have backed up and sent water to streets and subway stations, according to Seoul Metro. A number of subway stations were closed due to the flooding, with lines temporarily suspended Monday night. As of Tuesday morning, authorities were still working on reopening stations.
Several areas south of the Han River were hardest hit, including the affluent modern district of Gangnam where some buildings and shops were flooded and electricity was lost.
About 800 residents were either evacuated to schools and gyms or voluntarily sought shelter in local community centers as the flooding affected more than 700 homes and shops, according to authorities.
He also noted the need to review the country’s disaster management system, as extreme weather is expected to become increasingly common due to the climate crisis.
Several countries across East Asia are now seeing more intense daily rain, as the summer monsoons are expected to get stronger and more unpredictable as the Earth warms, according to the Intergovernmental Panel on Climate Change.
More torrential rain will hit Tuesday evening and continue into Thursday morning before ending Thursday afternoon, according to CNN meteorologists.
Areas already inundated could see an additional 300 mm (11.8 inches) of rain – potentially adding to flooding and mudslides.
Precipitation in Seoul usually averages 348 mm (13.7 in) in August – the wettest month of the year there. Several locations recorded so much rain in just one day.