Torrential rains fell on the southern port city of Busan and southeastern Korea on Monday, killing five people and leaving five more missing after a city bus was swept away by currents and a passenger car was submerged in an underpass.
A nuclear power plant was also shut down due to flooding.
Some parts of Busan saw up to 242 mm of downpours an hour with the average rainfall surpassing 130 mm. Traffic was halted in certain parts of downtown Busan, while portions of the city's subway lines were shut down for three to 10 hours.
Around 380 students at a girls' middle school in northern Busan were evacuated to higher ground around 1 p.m. after water from a nearby stream overflowed and inundated the lobby. The girls were later rescued by emergency personnel.
Later in the afternoon, rainfall submerged subways, forcing passengers across the city to use other forms of transportation. On the ground, the downpours forced high-speed KTX trains to slow to a crawl as they approached the city, resulting in massive delays.
Two Air Busan passenger planes scheduled to land at Gimhae Airport in Busan at around 2 p.m. were forced to turn around and return to Gimpo in Seoul.
The Korea Airports Corporation said low visibility and thunderstorm alerts were issued at 12:30 p.m. causing nine domestic flights to be canceled and delaying one international and eight domestic flights.
At around 3:54 p.m., the 65 kW Gori nuclear power plant was shut down due to flooding.
Suncheon in South Jeolla Province was also hit by heavy rains. Up to 60 mm of torrential rains fell on the area for around 40 minutes starting at noon, inundating an outdoor parking lot while landslides made several roads inaccessible. The average rainfall in Suncheon was 133 mm.
On Tuesday afternoon, showers are expected in Seoul. The Korea Meteorological Administration forecast overcast skies across the nation with showers expected in central and eastern parts.