Posted on Jan 15, 2023
0
ENE
Posted on Jan 15, 2023
0 0
ENE
9km

Distance

4.5 hours

Time

950m

Ascent

1498m

Highest point

6.5/10
Difficulty
Snow Icon | Hokkaido Wilds
Feb-Apr

Best season

Iwanai-dake 岩内岳 (1498m) is a conspicuous peak near the Japan Sea coast at the far western end of the Niseko Range. The northeastern ridge of the mountain offers some beautiful old-growth forest on its upper reaches, as well as a short and sharp alpine section. Views are spectacular across the Japan Sea and plains below. Snow quality can be some of the best in the range, if weather and timing favors you. With much of Iwanai-dake's northern aspect off limits to hikers, this route is a great way to experience what this unique, remote peak has to offer.

Route Map

Need to know details

Location

Iwanai-dake is a peak in the far western end of the Niseko Range in southwestern Hokkaido, Japan. This route up to the peak starts on the northeastern side of the mountain, far from the busier Iwanai Resort on the northern side.

General notes

The sprawling Iwanai Resort catski area on the northern side of Iwanai-dake limits somewhat skiing options for independent hikers seeking solid open freeski terrain – hikers are not allowed in the catski terrain to the north of the summit. This eastern side, however, offers just that – well-spaced old-growth forest and a gloriously open alpine section. The lower stands of newer-growth forests is a little tight, however, and there is a simple river-crossing to contend with at the base of the route. The river is not much more than a trickle though, and in classic Hokkaido style, there’s a plethora of concrete in the river – there are frequent man-made drops consisting of very handy concrete blocks that make for easy step-stones (you’ll likely need to remove skis).

The normal caveats apply to this west-of-the-range route – being close to the Japan Sea, it will be more frequently and directly buffeted by seasonal storms. Pick your day well though, and it will deliver some of the range’s best powder.

Hut
None
Route details

Park up at the forestry road entrance here, well to the side of the road so as to not block traffic (consider clearing a few meters more snow off to the side of the road). Head directly west to the Notaba-gawa 野束川 river, and follow it upstream to find a suitable spot to cross. There are a number of man-made drops, with concrete blocks that make suitable step-stones. If they’re covered with pillows of snow, take care! You’ll likely need to remove your skis for the crossing, but you shouldn’t need to get your feet wet.

Once on the other side of the river, head southwest across the band of flat land before gaining the main, broad eastern ridge. Follow your nose up this broad ridge to the summit. You may find the eastern side of the summit ridge to have a large cornice, so wrap around to the north to gain the narrow summit ridge.

Descend the way you came.

Route Timing
Up | 3hrs
Down | 0.5hrs

Transport

Public transport:

There is no public transport to this route.

By car:

There is very limited parking for this route – skiers will likely be parked on the side of the road (which is technically illegal, but unheard of being enforced). Therefore, make the time to clear a few meters off the side of the road, so as to get your vehicle as far to the side of the road as possible.

Physical maps
Print: HokkaidoWilds.org 1:25,000 TOPOMAP+
Niseko Backcountry map: Buy on Amazon.co.jp | See companion site for more purchase options
Official Topo Map: () – map no.

NOTE: The official 1/25000 topo map(s) above can be purchased for 350yen from Kinokuniya bookstore next to Sapporo Station or online (in Japanese).

Aspect
The main aspect skiers are exposed to on the descent and/or ascent is East. Other aspects that may also be encountered while following the route outlined on this page include: Northeast. Therefore, keep an eye on the weather forecast a few days ahead of your trip to monitor wind, snow, and temperature. Also, since this route is in the general vicinity of the Shiribeshi area, consider looking at the Japan Avalanche Network avalanche bulletins (updated Tuesdays, Thursdays, Saturdays at 8am) or the daily Niseko Avalanche Information website. These may give extra insight into avalanche conditions in the greater area around the route.

Snow and
route safety

Navigation is relatively straightforward on this route. If you’re skiing from the summit in an easterly direction, you will end up at the river eventually. Note however that the Ichinosawa Creek gully 一の沢川 is deep and has steep gully walls. Keep to the main broad east-northeastern ridge to be safe. The northeastern ridge will also be somewhat in the lee of storms, so care should be taken particularly after heavy snowfall and wind – slopes will likely be heavily wind-loaded. This will be particularly the case for the broad east-facing slope funneling into Ichinosawa-gawa 一の沢川. As noted above, Iwanai-dake’s proximity to the Japan Sea means that any strong wind forecasts should be taken seriously – the coast takes a beating with winds straight out of Siberia.

Iwanai-dake NE Ridge Difficulty Rating

Category

Grade

Points

Strenuousness

Vertical Gain

A

40

Time ascending

C

3

Technicality

Altitude

A

10

Hazards

C

6

Navigation

C

6

Totals

65/100

GRADES range from A (very difficult) to D (easy).  More details here. Rating rubric adapted from Hokkaido Yukiyama Guidebook 北海道雪山ガイド.

Weather forecast

Windy.com weather forecast for Iwanai-dake
Onsen nearby

Okaerinasai Onsen おかえりなさい温泉 (800yen, location), at the base of the Iwanai Resort area, has a gloriously hot natural onsen, both indoors and an outdoor bath. The onsen is open to day visitors from 10am – 9pm (10am – 3pm on Saturdays). The outdoor pool is open from 3pm. Other than the Iwanai Resort area, there is a relative dearth of onsen in the immediate Iwanai area.

Extra Resources
No extra English resources that we know of. If you know of any, please let us know in the comments.

Guide Options

If you’d like to ski this route and/or explore other Niseko areas together with a local certified guide, get in touch with Jun Horie. He’s a Niseko-resident guide with seven years experience advanced-level ski instructing in Austria (he speaks German as well as English and Japanese). He has also guided in New Zealand and has previously led guiding operations in Hokkaido before going independent. See a full list of English-speaking Hokkaido Mountain Guides Association (HMGA) guides on the HMGA website here

Iwanai Resort also offers guided tours in addition to their catski operation.

Show Full Route Notes Close Route Notes

Route Trip Notes

I’d been eyeing up this ridge for a while, as an alternative approach to Iwanai-dake that avoided the Iwanai Resort area. While the good folk at Iwanai Resort allow hikers up the northern ridge (see that route guide here), the terrain it gives access to is a bit limited. The large Kenbuto Gully bowl is interesting, but limited in vertical meters on the descent. 

This northeastern ridge, however, promises a much more mellow and long descent.

It was well into the spring season when I did the route. A real t-shirt layering sort of a day – very warm.

The river crossing was somewhat of a wildcard for me – there wasn’t much information online about exactly what sort of situation I would encounter. In the end, there were plenty of rocks and concrete blocks to step on. It was a hassle to have to take the skis off, but at least I didn’t have to take my boots off.

The trek across the flood flats was quick, and I was soon starting to gain altitude on the main ridge. Lower down, the trees were tight. These soon thinned out, however, to reveal some great playful terrain. The slope was mellow, but there were small spurs and micro-features that would be fun on the way back down.

The sun came and went as I ascended. Hot beaming sun one moment, cold air the next. I knew there was some rain forecast for later in the afternoon, so I was hurrying, trying to get to the summit and back down again before things got very damp.

Once above the treeline, the full Niseko Range stretched to my left eastwards. It’s not often one sees the range from this side, and certainly not from this side with such an expansive view of it. The western side of Iwaonupuri caught my eye – steep, rocky, remote.

To the north across Iwanai Bay was the Tomari Nuclear Power Plant – the only nuclear power plant in Hokkaido. Currently sitting idle while politicians twiddle their thumbs, waiting for public opinion to waver back towards support for less carbon-intensive electricity production.

I’d had high hopes of making it to the summit of Iwanai-dake. However, at around 2pmm, about 100m vertical below the summit, clouds were beginning to fill the sky more than before. The cloud cover started dropping in altitude, enveloping the summit.

With the forecast of rain later on, I decided this was my cue to head back for the day. I was about half way up the alpine section of the route, so I’d certainly not miss out on too much downhill. I ripped skins, sent the drone up, and tried my best to ski one-handed.

I was solo on this trip, but wanted to capture something of the amazing backdrop that Iwanai-dake offers to the hiking skier.

Once back into the trees, the mellow downhill did not disappoint. Rolling features kept things interesting until the new growth nearer the bottom of the route. From there it was a typical low altitude slalom back across to the river. Mercifully, I did not need to put skins back on for the short flatland section to the river. 

I once again removed skis for crossing the river, and was back at the car just in time for the skies to not open with rain, but to clear gloriously into blue sky – for the remainder of the day.

I patted myself on the back for being willing to turn back so close to the summit, but at the same time trued to swallow the irony of being ‘rewarded’ with blue skies and a clear summit…

Comments | Queries | Reports

Done this route to Iwanai-dake, or others nearby? Thinking of doing it? Please post any feedback, reports, or queries here. Thanks!

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Iwanai-dake NE Ridge Difficulty Rating

Category

Grade

Points

Strenuousness

Vertical Gain

A

40

Time ascending

C

3

Technicality

Altitude

A

10

Hazards

C

6

Navigation

C

6

Totals

65/100

GRADES range from A (very difficult) to D (easy). Hazards include exposure to avalanche and fall risk. More details here. Rating rubric adapted from Hokkaido Yukiyama Guidebook 北海道雪山ガイド.