Zaō Mountains
蔵王山ざおうざんZaō-zanEmerald crater lake, snow monsters and sulphur springs on the spine of Tōhoku.
The Zaō Mountains (蔵王山) are an active volcanic group on the border of Yamagata and Miyagi prefectures whose highest peak, Kumano-dake, reaches 1,841 m. They are famous for the emerald crater lake Okama and for the juhyō, fir trees encased in rime ice that form "snow monsters" each winter above Zaō Onsen.
Overview
The Zaō Mountains straddle the Ōu range between Yamagata city and the Miyagi side near Shiroishi. The summit area is a group of peaks around the Okama crater – Kumano-dake, the highest, Katta-dake with its shrine, and Goshiki-dake, the youngest cone, whose crater holds the lake.
Zaō is a place of two seasons: in summer, the crater lake and wide views draw visitors up the scenic mountain roads; in winter, heavy snowfall and fierce winds coat the Aomori fir forests in rime, creating the juhyō for which Zaō Onsen, one of Japan's major ski resorts, is known. The strongly acidic sulphur spring of Zaō Onsen has been used since ancient times.
Landscape and formation
Zaō is a stratovolcano group that has been active for about a million years. The present summit area formed within a horseshoe-shaped caldera; the Goshiki-dake cone within it is the youngest, and its crater hosts Okama, a lake about 360 m across whose colour changes with the light and weather. Eruptions in historical times, including the 19th century, have been phreatic, and fumaroles occur around the crater.
Winter monsoon winds from the Sea of Japan carry supercooled droplets that freeze onto the trees, building the rime-ice formations.
Highlights
Okama
御釜OkamaThe emerald crater lake of Goshiki-dake, symbol of Zaō.
Kumano-dake
熊野岳Kumano-dakeThe highest peak, 1,841 m, with the Zaō-san Jinja shrine and a monument to the poet Saitō Mokichi.
Katta-dake
刈田岳Katta-dake1,758 m, with the Katta-mine shrine and the car park of the High Line; the easiest viewpoint over Okama.
Juhyō
樹氷juhyōRime-covered Aomori firs forming "snow monsters" on the Yamagata side in mid-winter.
Ecology
Aomori fir forests on the upper slopes provide the framework for the juhyō; around the crater, volcanic gravel supports komakusa. The lower slopes carry beech forest.
Flora
Aomori fir
アオモリトドマツaomori-todomatsuThe tree of the snow monsters; forests have been damaged by insect outbreaks, and replanting is under way.
Komakusa
コマクサkomakusaGrows on the volcanic gravel of the summit area.
Fauna
Japanese serow
カモシカkamoshikaCommon on the snowy slopes.
Asian black bear
ツキノワグマtsukinowagumaPresent in the beech forests.
Culture
The name comes from Zaō Gongen, the protective deity of Shugendō first worshipped on Kinpu-sen in Yoshino, whose cult was brought to these mountains by ascetics; they became "Zaō's mountains". Shrines on Katta-dake and Kumano-dake served pilgrims from both sides. The tanka poet Saitō Mokichi, born at the Yamagata foot, wrote often of Zaō.
Zaō Onsen
蔵王温泉Zaō onsenA historic acidic sulphur hot-spring village and ski resort on the Yamagata side.
Katta-mine Jinja
刈田嶺神社Kattamine JinjaThe summit shrine on Katta-dake, with a lower shrine in Zaō town (Miyagi).
History
Heian period
Shugendō ascetics bring the worship of Zaō Gongen to the mountains.
1895
Phreatic eruption in the Okama crater.
1963
Zaō Quasi-National Park is designated.
Through the seasons
Spring
The Echo Line opens in late April with high snow walls; spring skiing at Zaō Onsen.
Summer
Okama and the summit ridge are at their most accessible; alpine flowers in July.
Autumn
Fine colours on the Echo Line and around Zaō Onsen in October.
Winter
Snow monsters, powder skiing and night illumination of the juhyō; the summit roads are closed.
Routes and trails
Katta-dake – Kumano-dake ridge
From the Katta-dake car park along the crater rim to Kumano-dake, about 40 minutes one way; easy.
Zaō Ropeway – Jizō-sanchō – Kumano-dake
From Zaō Onsen by ropeway to Jizō-sanchō at about 1,660 m, then about 1 hour; easy to moderate.
Zaō traverse
Longer ridge walks connect the Zaō peaks with Byōbu-dake and Fubō-san to the south, for experienced hikers.
Practical notes
- Zaō Onsen is about 40 minutes by bus from Yamagata station; the Miyagi side is reached from Shiroishi.
- The Echo Line and High Line are closed in winter and may close at other times because of volcanic activity or weather.
- Fog is frequent on the summit plateau; follow the markers.
- Zaō is monitored as an active volcano by the Japan Meteorological Agency, which publishes current information.
Frequently asked questions
How can the Okama crater lake be seen?
The easiest way is by the Zaō Echo Line and the Zaō High Line toll road to the Katta-dake car park, then a short walk to the viewpoint. The roads are open from spring to autumn, subject to volcanic and weather conditions.
When are the snow monsters at their best?
From about late December to early March, peaking in February, around the top station of the Zaō Ropeway above Zaō Onsen; they are lit up on some winter evenings.
How long does it take to reach Kumano-dake?
About 1 hour from the Zaō Ropeway's Jizō-sanchō station, or about 40 minutes from the Katta-dake car park via the ridge.
Is Zaō an active volcano?
Yes. The Japan Meteorological Agency monitors Zaō, and access to the Okama area can be restricted when activity increases.
Related
Sources
- 1.日本の主な山岳標高 (opens in a new tab) — 国土地理院 (Geospatial Information Authority of Japan)
- 2.火山登山者向けの情報提供ページ（蔵王山） (opens in a new tab) — 気象庁 (Japan Meteorological Agency)
- 3.山形県ホームページ (opens in a new tab) — 山形県 (Yamagata Prefecture)
- 4.宮城県公式ウェブサイト (opens in a new tab) — 宮城県 (Miyagi Prefecture)