Nightmare of "All 124 Dead" in Past Crash... Identity of the "UFO Cloud" Over Skies Near Seoraksan
by Heo Midam
Published 04 Feb.2026 10:43(KST)
Updated 05 Feb.2026 07:40(KST)
Lenticular clouds form when topographical and meteorological conditions coincide
They can also pose a threat to aircraft operations
1966 crash of UK carrier BOAC Flight 911
All 124 passengers and crew were killed
Last weekend, clouds with a unique UFO-like shape appeared in the sky over the Yeongbuk region of Gangwon Province, drawing public attention.
According to Yonhap News on February 4, flat and smooth clouds resembling UFOs were observed on January 31 in the skies over the Yeongbuk region, including Sokcho City and Yangyang County in Gangwon Province. At the time, the sky was clear with almost no other clouds, yet these clouds were seen only in the airspace near Seoraksan National Park.
These clouds are called "lenticular clouds," which appear locally only at specific spots under clear weather conditions. Lenticular clouds form when mountainous terrain such as Seoraksan and certain weather conditions coincide.
When airflow crossing a mountain range becomes stronger, cold and fast winds pass vertically over the mountains, causing the air to oscillate up and down like waves. At points where the air rises, the temperature drops, water vapor condenses, and clouds form, while in descending sections the clouds dissipate. As a result, a structure is created in which clouds are maintained only at specific altitudes and locations. When this phenomenon is repeated, clouds are generated only along certain layers above the mountain range, their edges remain undisturbed, and they take on a smooth shape, as if they were cut with a knife.
Because of this, lenticular clouds are characterized by their unique appearance resembling a saucer or UFO. Their shape does not change much even in strong air currents, and they can sometimes appear stacked in multiple layers vertically. However, they do not last for a long time, which makes them look even more mysterious.
Gong Sangmin, forecast analyst at the Korea Meteorological Administration, said, "When air is stable and strong winds blow over a mountain, forcing the air to rise and cool, saucer-shaped lenticular clouds can form," adding, "They are the result of terrain and weather conditions coming together at the same time." Lenticular clouds often do not bring rain or snow, so they can appear locally even when the weather is clear. In addition, because they are heavily influenced by topography, they are observed relatively often in the Yeongbuk region located between the East Coast and Seoraksan, as well as in the Jeju area near Hallasan.
Despite their mysterious appearance, they pose a threat to aircraft operations
However, despite their mysterious appearance, lenticular clouds can pose a threat to aviation safety. Near the atmospheric inversion layer where lenticular clouds form, strong winds crossing the mountains generate mountain waves, and these mountain waves in turn create severe turbulence, which can endanger aircraft operations.
In fact, in 1966, British BOAC Flight 911, en route from Tokyo Narita Airport in Japan to Hong Kong Kai Tak Airport, suddenly crashed near Mount Fuji, killing all 124 passengers and crew on board. An investigation found that lenticular clouds had been observed in weather satellite images about 30 minutes before the accident, and concluded that the aircraft encountered severe turbulence caused by mountain waves, leading to the crash.
© The Asia Business Daily(www.asiae.co.kr). All rights reserved.