Mount Seorak's fall foliage arrives in October for first time in 13 years

Fall foliage has arrived later than usual in Korea this year, primarily due to prolonged summer weather.

In a photo provided by the Korea Meteorological Administration, the first fall foliage is observed on Mount Seorak in Gangwon on Oct. 4. [KOREA METEOROLOGICAL ADMINISTRATION]

Fall foliage has arrived later than usual in Korea this year, primarily due to prolonged summer weather.

According to the Korea Meteorological Administration (KMA) on Monday, autumn leaves were first observed on Mount Seorak in Gangwon on Friday, six days later than in typical years. Last year, the first fall foliage on the mountain was recorded on Sept. 30, four days later than in average years.

The KMA marks the start of fall leaves on mountains when 20 percent of the treetops from the summit have turned autumn colors. Typically, the foliage spreads downward from Mount Seorak, which has high altitudes and cooler temperatures.

The KMA monitors the fall colors on 21 prominent mountains across the country, including Mount Jiri in the southern region and Mount Bukhan in Seoul. As of Monday, Mount Seorak is the only mountain where fall foliage has been observed.

This year marks the first time in 13 years that Mount Seorak has seen its leaves turn in October, the last time being Oct. 4, 2011.

The unusually high temperatures in September are seen to be responsible for the delayed foliage.

The average temperature on Mount Seorak was 14.2 degrees Celsius (57.6 degrees Fahrenheit), about three degrees higher than usual, with particularly warm mornings compared to previous years.

“Fall foliage on Mount Seorak began later than average because the daily low temperatures at the observation site were 11.6 degrees Celsius, compared to 10.4 degrees last year,” the KMA said.

First fall foliage on Mount Seorak [NAM JUNG-HYUN]

Peak foliage is also expected to arrive later due to the higher-than-average October temperatures.

The KMA forecast on Monday indicated that nationwide temperatures would remain similar to, or higher than, typical levels through Oct. 17, with midday highs between 21 and 26 degrees Celsius.

Peak fall foliage — when 80 percent of the mountain is covered in autumn colors — typically occurs around 20 days after the first observation of color change. Last year, Mount Seorak peaked on Oct. 23, six days later than the usual Oct. 17 date.

“The cold air from the north is not expected to descend in October, so temperatures will likely remain higher than average until early November,” said Ban Ki-song, senior managing director at K Weather, a private weather service provider.

“There is also a possibility that the peak foliage season will be delayed further than initially expected.”

In recent years, fall foliage has been delayed due to extended summers brought by climate change.

K Weather’s analysis shows that over the past five years, the first fall foliage on Mount Jiri has been delayed by 11 days and by six days on Mount Odae in Gangwon, compared to the 1990s. Peak autumn foliage has also been postponed by eight days on Mount Jiri and six days on Mount Palgong in North Gyeongsang.

Hikers pass by fall leaves on Mount Seorak in Gangwon on Sept. 29. [YONHAP]

Experts warn that climate change could also disrupt tree growth cycles by altering the balance of sunlight and temperature. If temperatures plunge abruptly after staying high, like this year, leaves may fall without turning color.

“The reduction in sunlight during fall, combined with current temperatures that differ significantly from what the ecosystem is used to, can prevent trees from functioning normally, causing green leaves to fall,” said Jeon Su-jong, professor at Seoul National University’s Graduate School of Environmental Studies.

This week, the temperature gap between day and night is expected to remain significant, with morning lows ranging from 9 to 17 degrees Celsius and midday highs between 18 and 26 degrees on Tuesday.

Cloudy skies are forecast to arrive on Tuesday afternoon and persist through Thursday, according to the KMA.

BY CHUN KWON-PIL, CHO JUNG-WOO [cho.jungwoo1@joongang.co.kr]