Zao's Okama Crater Lake and Frost-Covered Trees

Straddling the border of Miyagi and Yamagata prefectures, Mt. Zao is one of Tohoku's most dramatically varied mountain destinations — offering volcanic crater scenery in summer and autumn and the world-famous "juhyo" (frost-covered trees) spectacle in winter. The mountain's Okama Crater Lake sits at 1,758 meters elevation, its vivid emerald-green water contained within steep volcanic walls: a perfect natural jewel that changes color with weather and season, earning it the nickname "Goshiki-numa" (Five-Color Pond) for its ability to shift between green, blue-green, and deep blue.

Highlights

Okama is accessible in summer by the Zao Echo Line toll road, which climbs through alpine meadows to the crater rim viewpoint. The view of the lake, typically a deep emerald or turquoise, surrounded by the bare volcanic crater and (in early summer) patches of snow, is one of Tohoku's most striking volcanic landscapes. The Echo Line itself passes through a landscape of remarkable alpine beauty, with views across both Miyagi and Yamagata on clear days.

In winter, Zao transforms around its ski resort (one of Japan's largest) where the phenomenon of juhyo — fir trees and other conifers encased in rime ice and windblown snow into fantastic upright shapes — creates an otherworldly forest of white forms. Lit at night, the ice-covered trees resemble the "snow monsters" (yukimi dake) described in local legend.

Getting There & Tips

From Yamagata, bus to Zao Onsen in about 40 minutes. The Echo Line toll road operates May through November — check opening dates. In winter, ski resort gondolas access the juhyo viewing area.

Best Time to Visit

Summer–autumn for Okama; January–February for juhyo. The combination of onsen (hot springs) and juhyo viewing makes a winter visit particularly compelling.