South Korea grappled with heavy snowfall for a second day on Thursday, with dozens of flights cancelled, ferry operations suspended and at least four people reported dead in a bitter winter, though conditions showed signs of easing.

The winter snowfall was the third-heaviest in Seoul, the capital, since records began in 1907, the Yonhap news agency said, citing data from the city.

More than 40 cm (16 inches) of snow piled up in parts of Seoul by 8 a.m., forcing the cancellation of more than 140 flights, although weather officials lifted heavy snow warnings in the capital's metropolitan area by 10 a.m. on Thursday.

One person died and two were injured at a golf range after a net overladen with snow collapsed late on Wednesday, while another was killed in the similar collapse of a protective tent at a car park, media said.

Traffic accidents on highways east of the capital killed at least two more, reports showed. Police said 11 people were injured on Wednesday evening in a 53-vehicle pile-up on a highway in the central city of Wonju in Gangwon province.

Seoul's main airport, Incheon, was the worst affected, with passengers facing delays of two hours on average, while 14% of flights were delayed and 15% cancelled on Thursday, plane tracking website Flightradar24 showed.

Authorities said about 142 flights were cancelled, and operations of 99 ferries suspended on 76 routes by Thursday, authorities said, while media reported trains were also delayed.

Schools in the province of Gyeonggi adjoining Seoul received permission to close on Thursday if needed, provincial authorities said.

The unusually heavy November snow has been attributed to the warmer-than-usual temperatures of seawaters west of the Korean peninsula encountering currents of cold air.

Neighbouring North Korea has also received more than 10 cm (4 inches) of snow in some areas between Tuesday and Wednesday, state broadcaster Korean Central Television said.