More than 100 flights to and from Jeju Island, off the south coast of South Korea, were canceled or delayed amid heavy snow, the second major disruption in less than a month.

Some 109 flights scheduled to depart or arrive at Jeju International Airport were delayed, while 18 domestic flights canceled as of 1 p.m. in Seoul, Yonhap reported, citing Korea Airports Corp. Forecasters on Sunday issued warnings for snow and high winds on the island.

The Seoul-Jeju route was the busiest on the planet in 2017, with 65,000 trips between the island and the capital, according to data from OAG Aviation Worldwide Ltd. That’s almost double the 35,000 trips on the busiest North American route: Los Angeles to San Francisco.