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.

📚 Sources

The Zao crater lake Okama (Goshiki-numa), its scale of about 325 meters in diameter, the Zao Echo Line and the winter snow monsters introduced in this article are organized based on tourism information published by municipalities and tourism associations including Miyagi Prefecture and Zao Town, along with operator guidance such as the Zao Echo Line and the Zao Ropeway, and on-site lookout information. The period when Okama can be seen and the snow-monster peak draw on public information from official bodies and operators. Because the Echo Line opening status and ropeway operations change with the weather, please confirm official information before you visit.

Visitor Checklist

• Time estimate: About half a day for the Okama lookout and a stroll near the summit. Allow a full day to add a bath at Zao Onsen after descending.
• What to prepare: Weather near the summit changes easily and temperatures are low, so bring an extra layer or cold-weather gear. To see the winter snow monsters, heavy cold-weather gear and non-slip footwear are essential.
• Best timing: Okama can be seen from the Echo Line opening in late April to early November. The snow monsters peak from late January to February. Fog can hide Okama, so aim for clear weather.
• Suggested route: For Okama, drive via the Echo Line from stations such as JR Shiroishi-Zao and view the mysterious crater lake from the lookout. For the winter snow monsters, take a bus from JR Yamagata Station to Zao Onsen and use the ropeway. After descending, a soak at Zao Onsen is a pleasure.