Heavy rainfall causes major flooding in Seoul

Over the past two days, Seoul and the surrounding metropolitan area have been hit by up to 634mm of rainfall, marking the heaviest downpour of this rainy season. More heavy rain is expected starting July 20, which could worsen the existing damage.

According to the Korea Meteorological Agency (KMA), the Seoul metropolitan area experienced over 50mm of rainfall per hour this morning. Pyeongtaek received 88.5mm, Paju 69.8mm, and Yeoncheon-gun 58.5mm, severely limiting visibility. Generally, rainfall over 30mm per hour is considered heavy, and over 50mm is considered extremely heavy. Panmunjeom in Paju recorded 634mm over two days, nearly half of Paju's average annual rainfall of 1295.8mm. Incheon saw 328.5mm, and Seoul 208mm.

The deluge was caused by a seasonal rainfront stretching narrowly across the region. An irregularly developed mid-sized low-pressure system on this front, combined with a low jet stream from the southwest, brought in substantial water vapor.

The torrential rains have caused significant damage throughout the capital, flooding roads and homes and forcing evacuations in low-lying areas. Flood warnings were issued at eight points along the Imjin and Hantan rivers. Six hundred twenty-eight households, comprising 901 people, were temporarily evacuated from 36 municipalities and districts in eight provinces. The Ministry of the Interior and Safety upgraded the Central Disaster Safety and Countermeasures Centre from emergency level 1 to level 2. They raised the heavy rain alert from "caution" to "warning."

On Friday, a stationary front is expected to move south, bringing 20 to 30 mm of rain per hour in the morning, primarily affecting the southern part of the country. The Korea Meteorological Administration also forecasts up to 150mm rainfall in the Honam region by Friday. Additionally, on Saturday, a mid-scale low-pressure system developing over the West Sea is expected to begin spreading rain from the capital city across the entire country.


Sung-Jin Park psjin@donga.com