Iwaonupuri · Routes
↘ Iwaonupuri — NE Chute
⚠️ Every Yotei route is advanced, Complex avalanche terrain (max slope ~37–47°). Not a first tour; not for unguided AST-1 parties.
Steepness · profile
← Distance 5.0 km →
Per-segment terrain (data table)
| % | m | Steepness | Aspect |
|---|---|---|---|
| 0% | 761 | 17° | SW |
| 3% | 779 | 17° | W |
| 6% | 787 | 14° | W |
| 9% | 801 | 12° | E |
| 13% | 808 | 38° | S |
| 16% | 853 | 20° | E |
| 19% | 878 | 38° | SE |
| 22% | 951 | 41° | S |
| 25% | 1057 | 39° | SE |
| 28% | 1086 | 37° | SE |
| 31% | 1050 | 45° | NE |
| 34% | 1003 | 46° | E |
| 38% | 918 | 40° | NE |
| 41% | 868 | 40° | NE |
| 44% | 843 | 38° | NE |
| 47% | 825 | 33° | N |
| 50% | 829 | 46° | NE |
| 53% | 917 | 58° | NE |
| 56% | 1029 | 54° | E |
| 59% | 1104 | 28° | NW |
| 63% | 1097 | 36° | S |
| 66% | 1056 | 44° | E |
| 69% | 1007 | 46° | NE |
| 72% | 920 | 40° | NE |
| 75% | 887 | 27° | E |
| 78% | 856 | 31° | SE |
| 81% | 844 | 36° | SE |
| 84% | 819 | 36° | S |
| 88% | 812 | 24° | E |
| 91% | 807 | 9° | SE |
| 94% | 801 | 13° | S |
| 97% | 795 | 17° | SW |
| 100% | 782 | 17° | SW |
📖 Route guide
Iwaonupuri's NE Chute is one of the steepest committed lines in the Niseko Range — a 35–40° chute dropping about 200 m of its ~550 m total, over a 5.1 km, ~6 hour day graded 7.5/10 by Hokkaido Wilds. The baked 53° maximum is a local chute-wall value, not the ski line itself (median ~28°), but this is unambiguous ATES Complex (Level 3) avalanche terrain. Read this as a description of the ground, not a recommendation.
[The climb] From the plowed carpark at the end of Route 58 beyond Goshiki Onsen (~760 m), the route gains the summit plateau. The source strongly recommends ascending the same northeastern face you intend to ski — the skin up is your snowpack inspection. A waypoint on the eastern spur (~920 m) marks 'recommended to check snowpack (same aspect as chute)'.
[The chute — the crux] The entrance sits about 50 m north of the summit plateau. The top is a prominent convex roll: what lies below is not visible until you are well over it. The first third is committing, with very little escape to the sides; below that the chute widens considerably to skier's left, with bushy shrubs to skier's right. Minor wind slab has been observed at the very top. Snowpack stability is everything on this line.
[Cautions] The northeastern side of the mountain is seldom travelled and relatively remote — be fully self-sufficient. Iwaonupuri is an active volcano of the JMA-listed Niseko group (no alert level currently operated); the crater area west of the summit is sulphur/geothermal ground. Check the Niseko avalanche bulletin and the Japan Avalanche Network SW Hokkaido bulletin before every tour.
🚗 Access & logistics
Start & parking: The large plowed area at the end of snow-clearing on Route 58, just beyond Goshiki Onsen (~760 m). Can fill by ~9 am on weekends — start early.
Getting there: ~23 km from central Hirafu. No public transport; a taxi runs ¥7,500–8,000 one-way. Expect packed snow and ice on the roads.
Onsen: Goshiki Onsen (10:00–19:00, ¥800) is right by the carpark; Yukichichibu (12:00–19:00, ¥700, closed Tue) is nearby. Hours vary — confirm locally.
Avalanche info: Check the Niseko Avalanche Institute bulletin and the Japan Avalanche Network SW Hokkaido bulletin before departing.
📍 Yotei — local notes
- The summit dome is featureless — in a whiteout, navigate by compass bearing.
- The crater rim can be corniced — keep well back from the edge.
- Above ~1300 m the snow is often wind-hammered or icy — crampons or ski-crampons are commonly needed, and many parties descend from here.
- Near the summit the slope faces every aspect — wind-loading and sun change fast; read the bulletin’s full rose.
- On a symmetric cone with a featureless summit it’s easy to drop the wrong aspect in flat light and descend into a different valley than you climbed — confirm your descent bearing before dropping in.
📋 Trip plan
🏔 Terrain (auto)
Slope-based estimate — not an official ATES rating.
🌡 Today's conditions
…
All values are estimates. Defer to official avalanche + weather bulletins.
⚠️ Avalanche bulletin (read first)
Today's danger rating + avalanche rose (aspect/elevation) come from the official bulletin — check it before you go.
📝 Pre-trip checklist
🗺 Hokkaido Wilds · Rob Thomson — HokkaidoWilds.org · CC BY-SA 4.0
🎥 山のまこちゃん · Video report
山のまこちゃん (Yama no Makochan) covers Yotei routes on video — embedding pending his permission.
Route data source: Rob Thomson — HokkaidoWilds.org · CC BY-SA 4.0 · ↓ Download GPX