Sobaeksan National Park

Sobaeksan runs to 1,439 metres at Birobong along a broad ridge straddling the provincial border, and unlike most Korean mountains the top is not rock but open grass and low scrub, swept by wind - which gives it long uninterrupted ridge walking and two distinct seasons that draw people. In late May and early June the cheoljjuk, royal azalea, flowers across the upper slopes in pink drifts, and Yeonhwabong and the ridge toward Birobong are the places to see it. In January the same exposure produces sanghogo, rime ice, coating the grass and the stunted trees in white feathers, and the ridge becomes one of the best winter walks in the country - and one of the coldest, with wind chill on the open top that catches people out. Below are Huibangsa temple and its waterfall, Buseoksa at Yeongju on the far side, and the Sobaeksan astronomical observatory on a spur.

What you actually see

• The royal azalea - pink across the upper slopes in late spring.
• The rime ice - white-feathered grass and trees in January.
• The open ridge - grass rather than rock along the top.
• The observatory - the astronomical station on the spur.

When to go

Late May to early June for azalea; January and February for rime ice. Both draw crowds and the azalea window is short and moves with the season.

Honest expectations

The summit ridge is fully exposed - winter wind chill is severe and every year catches unprepared walkers. Crampons are necessary in snow. Climbs from all gates are long, four hours or more return.

Nearby

Danyang and Gosu cave are north-west; Buseoksa and Yeongju are on the southern side.