South Korea is experiencing more frequent and intense short-duration rainfall events that cause repeated flooding across the country [1].
This shift in weather patterns suggests that traditional infrastructure may be unable to handle the increasing volume of water delivered in brief windows. The trend is linked to rising temperatures, which enhance the atmosphere's capacity to hold moisture [1].
Analysis of meteorological records spanning 113 years shows a clear trend toward these extreme events [1]. Last year, 15 locations recorded extreme rainfall exceeding 100 mm per hour [1]. These areas included Gunsan, Seosan, Sancheong, and 12 other locations [1].
Scientists describe this phenomenon as “super CC.” The mechanism is driven by thermodynamics: for every 1 °C increase in temperature, the atmospheric water-vapor capacity increases by approximately seven percent [1]. This additional moisture provides the fuel for more powerful rain clouds.
Son Seok-woo, a professor in the Department of Earth and Environmental Sciences at Seoul National University, said that while total precipitation and the number of rainy days were lower than average last year, the intensity of the rain that did fall was unprecedented.
"It seems that much more powerful concentrated heavy rain was created over a short period of time than usual," Son said [1].
These concentrated bursts of rain can overwhelm urban drainage systems faster than steady, long-term rain. This creates a high risk of flash flooding even in years where the overall annual rainfall remains below the historical average [1].
“Extreme rainfall exceeding 100 mm per hour recorded in 15 locations last year.”
The transition toward 'super CC' events indicates that South Korea's climate risk is shifting from total annual rainfall volume to peak intensity. This means that disaster prevention strategies must pivot toward managing extreme hourly surges rather than seasonal averages to prevent urban flooding.
