What Are Zao's Snow Monsters, and When Can You See Them?

Published 2026-10-04 · Sources checked 2026-10-04 · Treasure Hunting Co., Ltd.

This guide is for visitors who want to see the snow monsters of Zao, the frost-covered trees known in Japanese as juhyo. It explains how they form, where to see them from Zao Onsen in Yamagata City, and when the season runs. It also explains why the trees that carry them are under threat.

We used pages from Yamagata Prefecture, its official tourism site, the prefecture's landscape site, Yamagata City and the Prefectural Council for the Revival of Juhyo. All were read on 2026-10-04. The season depends on the weather, so check current conditions before you go.

What a snow monster is

Juhyo form on Oshirabiso trees, a kind of fir also called Aomori todomatsu. The prefecture's tourism site describes three steps that repeat through the winter:

• Icing. The seasonal wind carries droplets of water that are below freezing but still liquid. When they hit the trees, they freeze at once.
• Snow. Large amounts of snow are caught in the gaps in the ice.
• Sintering. The ice and snow stick together and pack hard.

As these steps repeat, the trees grow into large white shapes. Their fluffy look gave them the nickname "snow monsters". The prefecture says the larger ones are over 5 m tall.

Why they form at Zao

Yamagata Prefecture gives three reasons:

• A strong seasonal wind from Siberia brings a lot of supercooled water droplets and snow.
• Aomori todomatsu, an evergreen conifer that ice and snow stick to easily, grows wild here.
• The snow is deep, but not so deep that it buries the trees.

The prefecture adds that juhyo form only near the summits in midwinter, where it can fall to minus 15°C. They became known across Japan under the name juhyo in the Taisho era, early in the twentieth century.

Zao is not the only place. The prefecture lists Hakkoda, Hachimantai and Moriyoshi, and Azuma as other mountains in the Ou range where juhyo can be seen.

Where to see them

The easiest way up is the Zao Ropeway, which starts in Zao Onsen. You ride two lines:

• The Sanroku line, from Zao Sanroku Station to Juhyo Kogen Station. It takes about 7 minutes.
• The Sancho line, from Juhyo Kogen Station to Jizo Sancho Station. It takes about 10 minutes.

Jizo Sancho Station stands at 1,661 m. The prefecture's landscape site says juhyo cover the whole west slope of Mount Jizo (1,736 m), seen from the viewing area there. You can see them as soon as you leave the ropeway.

The prefecture's tourism site says you do not need to ski to see them. Non-skiers can ride the ropeway, or join the evening snowcat tour described below.

From Zao Onsen Bus Terminal, the ropeway's base station is a 10 to 15 minute walk. Sources differ on the exact time.

When to go

Official pages give different windows, which shows how much the season moves with the weather:

• Prefecture tourism site, juhyo page: usually late December to late February. The same page's details box says late December to mid-February.
• Prefecture tourism site, English page: December to February, at their best in February.
• Prefecture tourism site, juhyo feature: best from late January to late February, with the whole season from late December to late March.
• Yamagata City: the trees grow from late December to early March, when the Zao Juhyo Festival is held.

Early and mid-February fall inside every one of these windows. The feature page warns that the season is very crowded. The prefecture also notes that sight can be lost suddenly on unstable winter days.

Day, night and the snowcat tour

The prefecture's juhyo feature listed these for the 2025-26 season:

• Daylight viewing: 08:30 to 17:00, late December to about late February.
• Light-up: 17:00 to 21:00, from 27 December 2025 to 22 February 2026. Coloured lights shine on the trees around the ropeway and Jizo Sancho Station.
• Night snowcat tour: a heated snow vehicle from Juhyo Kogen Station, on the same dates. Departures from Zao Sanroku Station were at 17:00, 18:00, 19:00 and 20:00. Riders were asked to gather 20 minutes before.
• Zao Juhyo Festival 2026: 27 December 2025 to 23 February 2026, with fireworks and a torch-lit ski run at night.

The light-up page adds several warnings:

• It can be cancelled in bad weather.
• On some days the trees cannot be seen at all.
• Temperatures fall to minus 10°C or lower, so dress for serious cold.
• You cannot bring skis or snowboards to the light-up.

Dates for the 2026-27 season were not on the pages we read. The ropeway operator posts them on its own site.

Why the snow monsters are at risk

Oshirabiso grows wild on Zao between about 1,300 m and 1,700 m. The Prefectural Council for the Revival of Juhyo says many of the higher trees have died, mainly from insect damage.

• Juhyo still form on dead trees, but they are thinner, because there are no leaves or branches.
• Dead trees will fall in time. Juhyo may then disappear from the damaged areas.
• Near the top of Mount Jizo, where the damage is worst, no young trees are growing. The forest is unlikely to recover on its own.

The summit forest is national forest. The Forestry Agency's Tohoku office has been moving young trees from healthy areas and raising seedlings from local seed. A Yamagata City message from 2022 named a moth and bark beetles as the insects involved. It added that warming may be behind the damage.

The prefecture's juhyo feature warns that Zao's snow monsters may not look the same in the near future.

What we could not verify, and therefore left out

• Ropeway fares, and the price of the light-up and the snowcat tour. These are on the ropeway operator's pages, which we did not use for prices.
• Dates for the 2026-27 light-up, snowcat tour and festival.
• How many trees have died, and which parts of the slope still have healthy juhyo.
• Juhyo on the Miyagi side of Zao, or in other parts of the range. This guide covers only the area reached from Zao Onsen in Yamagata City.

Related guides

• How do you get to Zao Onsen from Tokyo?
• How do you stay safe in Zao? Volcano, snow, bears and 110/119

Sources

All URLs retrieved 2026-10-04.

1. 蔵王の樹氷 (やまがたへの旅, Yamagata Prefecture official tourism site) — (icing, snow and sintering; Oshirabiso; season late Dec to late Feb and late Dec to mid-Feb; non-skiers; walk of about 15 minutes)
2. Juhyo / Snow Monster (STAY YAMAGATA, Yamagata Prefecture official tourism site) — (nickname; December to February, best in February)
3. 蔵王の樹氷を楽しもう！冬の絶景＆アクセス完全ガイド (やまがたへの旅, Yamagata Prefecture official tourism site) — (best and whole season; crowding; 2025-26 daylight, light-up, snowcat and festival dates and times; future warning)
4. 蔵王の樹氷 (Yamagata Prefecture) — (three reasons; minus 15°C; Taisho era; over 5 m; other mountains; sudden loss of sight)
5. 蔵王ロープウェイ (やまがたへの旅, Yamagata Prefecture official tourism site) — (stations; Sanroku line about 7 minutes; Sancho line about 10 minutes)
6. 蔵王ロープウェイ地蔵山頂駅からみる樹氷群 (やまがた景観物語, Yamagata Prefecture) — (Jizo Sancho Station 1,661 m; west slope of Mount Jizo 1,736 m; seen on leaving the ropeway; 10 minutes on foot)
7. 樹氷ライトアップ (やまがたへの旅, Yamagata Prefecture official tourism site) — (light-up area; cancellation; trees not visible; minus 10°C; no skis or snowboards)
8. 蔵王樹氷まつり (Yamagata City) — (growth period late December to early March; festival)
9. オオシラビソについて (Prefectural Council for the Revival of Juhyo, Yamagata Prefecture) — (1,300 to 1,700 m; insect damage; thinner juhyo; no young trees near Mount Jizo; national forest; Tohoku office work)
10. 市長のやまがた自慢「蔵王の樹氷を守る」 (Yamagata City) — (2022 message: moth and bark beetles; warming)