A rare “winter typhoon” is sweeping across South Korea on March 18, bringing heavy snow and strong winds due to a polar low-pressure system formed by frigid Arctic air. The system, fueled by temperatures as low as -40°C, is creating blizzard conditions nationwide. In Seoul, the latest heavy snow warning on record has been issued, with up to 10 cm of snowfall expected. This marks the first time in six years that such a powerful polar low, with wind speeds reaching 20 meters per second—comparable to a typhoon—has passed over the country.
According to the Korea Meteorological Administration (KMA) on March 17, a mass of Arctic air moved over the warm waters of the West Sea overnight, generating heavy snow clouds. As a result, most of the country is under a heavy snow warning on March 18, breaking Seoul’s previous record for the latest heavy snow warning, set on March 9, 2010.
Snowfall is expected to reach 3 to 10 cm in Seoul and surrounding areas, 3 to 30 cm in Gangwon Province, 1 to 15 cm in the Gyeongsang region, 1 to 10 cm in Chungcheong, 1 to 8 cm in the Honam region (Gwangju and Jeolla Provinces), and 1 to 5 cm in Jeju’s mountainous areas. In Gangwon’s mountainous regions, snow may fall at a rate of 3 to 5 cm per hour, while other areas will experience snowfall of 1 to 3 cm per hour. Some regions may see rain instead, with 10 to 20 mm of precipitation expected.
Gangwon and the East Coast have already seen heavy snowfall since March 16 due to strong easterly winds. Some areas have accumulated over 40 cm of snow on March 17, with snowfall reaching 42.5 cm in Hongcheon, 38.4 cm in Samcheok, and 34 cm in Daegwallyeong. With additional snowfall expected, total accumulation in some regions could reach mid-winter levels.
This snowstorm is driven by a polar low. When frigid Arctic air collides with the relatively warm 10°C ocean water, it creates highly unstable atmospheric conditions, forming a swirling low-pressure system. Cold air, being heavier, rapidly sinks, intensifying the vortex at lower altitudes. This is a polar low, meaning a low pressure system originating from polar regions like the Arctic.
These systems bring typhoon-level winds. While typhoons require minimum wind speeds of 17 m/s, polar low-pressure systems moving inland can generate winds of up to 20 m/s. Strong winds are sweeping through Seoul, the capital region, and Korea’s western areas on March 18. As the system moves quickly eastward across the country, it continues to produce wind speeds of around 15 m/s, creating typhoon-like conditions—except with snow instead of rain. Thunder and lightning may also accompany the storm.
Cold weather will continue as the polar low pressure system carries Arctic cold air. Morning lows on March 18 will range from -3°C to 3°C, while daytime highs will be between 3°C and 9°C. The wind chill has dropped to -4°C in Seoul and -8°C in Daejeon. The cold is expected to intensify on March 19, with lows falling to -6°C to 1°C and highs ranging from 6°C to 10°C.
This is the first time in six years, since March 2019, that a polar low has hit South Korea. At that time, strong winds and heavy snow covered Jeongseon in Gangwon with 15.9 cm, Pyeongchang with 15.1 cm, and Hongcheon with 14.3 cm. Winter-level snowfall also affected Gapyeong in Gyeonggi (6 cm) and Bonghwa in North Gyeongsang Province (12.6 cm). The strong winds caused a 44-ton tugboat to sink near Songi Island in Yeonggwang, leaving one person missing, and a power failure halted a Bundang Line train between Wangsimni and Seoul Forest stations.
