'Super El Niño' could bring roller-coaster winter weather to Korea
Pedestrians in warm attire walk along a street in Seoul, Wednesday, as morning temperatures in the city dropped to 9.3 degrees Celsius. Yonhap
Wild temperature swings are expected to continue through the winter, with what could be the strongest El Niño on record forecast to peak toward the end of the year, raising the likelihood of a “roller-coaster winter” marked by mild spells interrupted by sudden cold snaps.
According to the Korea Meteorological Administration (KMA), morning lows on Wednesday plunged by around 10 degrees Celsius from the previous day, reaching 9 degrees in Seoul and 3 degrees in Daegwallyeong, Gangwon Province. Temperatures are expected to gradually rise above the seasonal average over the weekend before plunging again, with lows reaching 3 degrees by the middle of next week, pointing to continued sharp fluctuations.
The erratic weather is typical of autumn, when migratory high- and low-pressure systems pass through the Korean Peninsula in succession. Cold winds blowing down from the north are battling warm, humid southerly winds originating over the western Pacific, where sea temperatures are higher than normal, causing weather conditions to fluctuate sharply.
Such unpredictable conditions are expected to persist through the winter, driven in part by a “super El Niño.” The World Meteorological Organization forecasts that sea surface temperatures in the El Niño monitoring region will be 3.7 degrees Celsius above average from October to December. That would far exceed the previous record of 2.6 degrees, set between November 2015 and January 2016.
Frost covers the Daegwallyeong area in Pyeongchang County, Gangwon Province, Oct. 6, when the season’s first cold wave advisory was issued. Yonhap
El Niño is a climate phenomenon in which sea surface temperatures in the central and eastern equatorial Pacific remain at least 0.5 degrees above average. Events in which temperatures rise more than 2 degrees above average are classified as super El Niño episodes.
El Niño’s effects on the Korean Peninsula are most pronounced in winter. As the phenomenon intensifies, convective activity over the western Pacific weakens, generating high-pressure circulation near the Philippine Sea. Atmospheric waves transmit the effects eastward, strengthening a high-pressure system east of Japan. Warm, humid southerly winds then flow toward the Korean Peninsula along the system’s periphery, bringing above-average temperatures and increased precipitation.
However, sudden cold snaps can occur when cold air from the north surges southward. At times, cold Arctic air may descend abruptly and force temperatures to plunge, particularly as sea ice in the Barents and Kara seas north of Europe melts almost completely, according to the report.
“When temperatures are around 5 degrees above zero and air at minus 5 degrees suddenly moves in, that creates a 10-degree difference,” KMA forecaster Woo Jin-gyu said. “The cold people feel can be much more severe than the absolute temperature alone would suggest.”
A similar pattern of sharp temperature swings was observed from late 2015 to early 2016, during a strong El Niño event. The national average temperature in December 2015 was 3.2 degrees, the warmest December since modern meteorological observations began in 1973. Just over a month later, however, Jeju Island issued a cold wave advisory for the first time in seven years, while Seoul’s lowest temperature plunged to minus 18 degrees.
Snow and rain accompanying cold spells are another potential hazard. During the winter of 1997, when El Niño reached its strongest level on record at the time, precipitation was three times the seasonal average. In January 2016, Jeju was hit by record snowfall of 12 centimeters in a single day, causing significant damage.
Experts urged authorities to step up preparations for potential weather-related disasters, warning that forecasts for the coming winter remain highly uncertain.
“An El Niño of unprecedented intensity will amplify weather fluctuations,” said Lee Myung-in, a professor at the Ulsan National Institute of Science and Technology. “We need to prepare for heavy snowfall and sudden cold snaps based on the worst-case scenario.”
This article from the Hankook Ilbo, the sister publication of The Korea Times, is translated by a generative AI system and edited by The Korea Times.