Tropical cyclones on the planet are bred in regions from the western Pacific to the north of the equator. The Philippines, a country where twenty cyclones hit on an annual average, is the most exposed region to the cyclones. Passing the Philippines, tropical cyclones then travel northwest, toward the direction of the coastal southeast of China. Then, cyclones hit the Korean peninsula and Japan with strong winds and rainfall. 

South Korea extends between latitudes of 44 to 48 degrees, where the Kuroshio currents hit Korea. Due to the warm Kuroshio currents, typhoons get sustained at higher intensity, which later allows an intense typhoon to hit Korea or western Japan. Since 2000, six typhoons, all within Category 1 intensity or higher, have hit South Korea within the time period between Aug 31 and Sept 12. However, in 2003, The Violent Typhoon Miami, was the strongest typhoon landfall in South Korea in recent decades. The typhoon was classified as a category 3, which replaced the previous record held by Typhoon Sarah in 1959. For recent typhoons, two very strong typhoons hit Korea in 2020, which both hit South Korea a few days apart.

However, the concern within typhoons hitting Korea aren’t strong winds, but rather intense rainfall. Due to rainfall, floods occur often, as the most intense rainfall can reach 500 millimeters in 24 hours. Fatalities from typhoons have been reduced from better warnings and flood risk management. The death toll of 669 from Sarah(1959) decreased to 117 during the stronger Miami(2003).

Image Source : https://edition.cnn.com/2022/09/07/asia/typhoon-hinnamnor-south-korea-intl-hnk/index.html

References :

Person. (2023, August 31). [contribution] understanding the impact of typhoons in Korea. koreatimes. https://www.koreatimes.co.kr/www/biz/2023/11/602_357988.html