Ansei Crater (Kamihoro Valley)

安政火口 | Nukkakushi Crater

Posted on Mar 7, 2023
Posted on Mar 7, 2023
0 2


4 hours





Highest point

Snow Icon | Hokkaido Wilds

Best season





Ansei/Nukkakushi Crater ヌッカクシ(安政)火口 (1450m) is a steaming, active geothermal valley high above Tokachi-dake Onsen area near Furano-dake in the Tokachi Range in central Hokkaido. With a parking area and trailhead at 1260m, this area can be a veritable playground for the discerning backcountry skier. You'll need to be willing to explore and scramble somewhat, but given a few days of snowfall with little wind, this entire valley can be a smorgasbord of deep, steep, and lappable skiing. Apre ski hotspring options also abound here, with some of the best in Hokkaido.

We visited this route on Feb 11, 2023

The crew: Tim, Timbah, Alex, Simon. Extra photos by Simon.

Last updated Feb 11, 2024


Route Map

Need to know details


Ansei Crater sits at the head of the valley east (uphill) from Ryounkaku Onsen in the Tokachidake Onsen area, at the southern end of the Daisetsuzan National Park in central Hokkaido. The start of this route is at the large snowplowed public parking area adjacent to Ryounkaku Onsen.

General notes

Usually on, ski touring routes generally have some sort of destination or specific skiing zone in mind. This route is a bit different. Here, we’re simply making an attempt at documenting some of the exploratory backcountry ski options in the valley east of Ryounkaku Onsen in the Tokachi Range. Being entirely in the alpine, this area will be very condition-dependent, but on the right day will offer some superbly accessible terrain ripe for the lapping.

Generally speaking, vertical gain and descent are fairly limited in this valley, but it does offer some compact, relatively protected, and sometimes steep bowls and gullies.

This area is very popular among winter mountaineers, with the entire rocky, craggy, cliff-bound western side of Kamihorokamettoku-yama 上ホロカメットク山 (1920m) a veritable smorgasbord of mildly technical winter climbing opportunities. As such, this area has a large number of named features, which we have tried to include in our printable PDF topomap of the area.

Route details

Head east from the public car park adjacent to Ryounanaku Onsen, keeping high, following the summer trail marked on maps. Follow the summer trail to where it crosses the Nukkakushi-furano River ヌッカクシ富良野川, and then head east along the valley from there to the ‘crater’. The crater is less a crater than a steaming bit of gully. Explore slopes as you desire on either side of the valley, as well as at the head of the valley. Return the way you came.

Route Timing
Up | 1.5hrs
Down | 0.5hrs

This ski tour doesn’t really have a specific goal or destination in mind – just skiing up to the crater and then back via your skin track will likely take less than two hours. On the other hand, with good snow and good visibility, you could happily make a full day out of this area, lapping slopes and exploring the various nooks and crannies.


Public transport:

The trailhead is accessible by public bus from Kamifurano JR train station – get off at the Ryounkaku Bus Stop 凌雲閣バス停. The trip will take about 40 minutes from the train station. The bus is run by the Kamifurano Town council. Timetable information is here: As of March 2023, the earliest bus bound for Ryounkaku Onsen was at 8:52am (arriving at Ryounkaku Onsen at 9:37am). There are only three buses per day heading up to the onsen (last one at 4:31pm). From Ryounkaku Onsen, as of March 2023, there were buses heading back down to the train station at 9:47, 13:37, and 17:27. Note that the bus goes via Hakuginso Lodge.

By car:

The trailhead is easily accessible by vehicle – it’s at the large snowplowed public parking area adjacent to the Ryounkaku onsen at the very top of the Tokachidake Onsen area. There’s room to park at least 30 cars in this car park.

Physical maps
Official Topo Map: Tokachidake (十勝岳) – map no. NK-54-7-8-2

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).

The main aspect skiers are exposed to on the descent and/or ascent is South. Other aspects that may also be encountered while following the route outlined on this page include: North. 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 Furano area, consider looking at the Furano Avalanche Center (on Facebook). They issue sporadic observations throughout the season which may give extra insight into avalanche conditions.

Snow and
route safety

At, we typically post routes on terrain with relatively low complexity when it comes to avalanche exposure. Much of the interesting skiable terrain in this Ansei Crater valley, however, is fairly high exposure, with some complexity when on the valley floor. Skiers should keep highly cognizant of the terrain in the area and should be particularly confident in their ability to assess snowpack stability on the aspects and in the terrain features they intend to ski. Note also that access to drop-in points higher up the valley walls will likely be via wind-scoured spurs – measures should be taken to reduce exposure to fall hazards.

Ansei Crater (Kamihoro Valley) Difficulty Rating





Vertical Gain



Time ascending















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 weather forecast for Ansei Crater
Onsen nearby

The natural choice for a post-ski onsen hotspring soak is Ryounkaku Onsen 凌雲閣温泉 (location, 800yen) next to the car park. The outdoor baths look east, out over the valley you’ve just skied. Just down the road is Kamihoroso カミホロ荘 (location, 6ooyen), with wood-lined outdoor baths that look west across the Furano plains. Slightly further afield is the wildly popular Hakuginso Lodge 白銀荘 (location, 700yen), with the largest outdoor bath facility in the area. If you’d prefer a wilder experience, there’s the Fukiage Onsen 吹上温泉 (location, free) – free wild onsen in the woods, accessed via a short 3 minute walk from the carpark.

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 peaks in central Hokkaido together with a local certified guide, get in touch with Yasuko Kikuchi. Born and raised in Hokkaido, she’s a JMGA-certified guide now based in Sapporo. Her outdoor experience is broad and worldwide, having worked as a Canadian Ski Patrol member, and has sumitted a number of 6,000m+ peaks around the world. She speaks good English, and can arrange transport to and from central Hokkaido. In addition to Yasuko, also see a full list of English-speaking Hokkaido Mountain Guides Association (HMGA) guides on the HMGA website here

Support us

Like this content? Buy the team a coffee. 50% of tips go to the Hokkaido Wilds Foundation.

Show Full Route Notes Close Route Notes

Route Trip Notes

It had long been on the back-burner to have an explore up the Kamihoro Valley behind the Ryounkaku Onsen. Haidee and I had gone up that way a couple of years back hoping to have an explore, but we got skunked by the weather – low cloud and high winds meant we had no visibility. We went for a short walk on snowshoes anyway for half an hour before retreating to the onsen for a long soak.

Today’s weather was about as far from that socked-in mess as it could have been. Crisp blue skies with hardly a breath of wind. And it was cold. Our 8am start felt like much earlier. Starting at 1200m is always going to be cold here in Hokkaido.

Simon and Alex met Tim and me at the large plowed car park and we all got ready to go. Tim and I got away slightly sooner than Simon and Alex, and were basking in the sun, looking over to the many gnarly lines on Furano-dake’s eastern face, when we got a call on the radio.

It was Alex.

“You guys should go on ahead,” she said, sounding a bit dejected. “We’ve locked our car but misplaced the car key. It fell behind the rear wheel, so we have to jack the car up to have a better look.”

The weather was looking stellar for most of the day, so Tim and I headed back to the car park to help them find their key.

After jacking the car up and pocking and prodding, we finally found it. It had fallen behind the back wheel, hit something, ricocheted off it and fell far away from the wheel in wrist-deep pow under the car.

Crisis averted, we all got on our way.

Being my first time to the valley in clear conditions in winter, it was very interesting to see some familiar peaks from a new perspective.

Kamihorokamettoku-yama, where we’d hunkered down for two full days during a typhoon on the Daisetsuzan Grand Traverse was directly in front of us.

Gake-one ridge 崖尾根 was to our left, leading up to the summit of Sandan-yama.

And of course Furano-dake, which we’ve hiked and skied before, was to our right.

Tim had pored over topomaps of the area, and had about 1,001 lines in his back pocket, all demanding to be skied. 

We were all hopeful today would prove to be decent enough conditions to enjoy some of what this valley had to offer.

The first possibility on the cards was a gully a few gullies west of Meoto-iwa 夫婦岩. We set a climbing traverse line up to the gully, in the hopes the gully had been protected from the high winds of the previous few days.

If nothing else, the surrounding scenery was superbly photogenic.

There were a few other climbers in the area. A party of three winter hikers, slowly making their way down the wind-scoured ridge from Sandan-yama. A solo skier with a European accent overtook us on a mission to find some good skiing terrain.

We made it to our intended gully in good time, and Tim quickly but carefully struck out into the middle of it to see what the conditions were like. We would end up climbing higher, but we wanted to get a feel for what we were in for.

“This isn’t bad,” radioed Tim. “If it’s all like this, it could be a good time.”

He then returned to the ridge along his skin track, and we carried on up.

Where Tim had taken a look at the surface conditions was only about half way up the gully. About three-quarters up, I took a turn at seeing what the conditions were like, as they were looking a bit suspicious. Where Tim had been lower down was on some old avalanche debris, and above that, the slope looked very smooth.

A long arching traverse confirmed what we’d been suspecting. Much of the gully was a thick-ish dust-on-crust situation. We decided it wasn’t worth climbing much higher, as we were keen to head deeper into the valley before the forecasted wind and cloud moved in in the late afternoon. We ripped skins and made the most of what we had.

From the base of the gully, we donned skins and headed up to take a look at the crater. In reality it was a steaming gully floor, but fun nonetheless.

As we were having a rest and bite to eat, we saw the skier with the European accent clambering up a wind-scoured ridge.

Good keen man.

We had a poke at another small gully, this time on the eastern aspect. The snow was OK for the first 50m or so, but the surface conditions quickly deteriorated.

The weather was coming in too. We had one last fun downhill blat.

Photos here by Simon!

The return to the car park near Ryounkaku Onsen was a great fun blat along the skin track. Except for the short uphill bootpack in hip-deep snow…that was 15 minutes of hard slog.

Instead of going to Ryounkaku Onsen for the post-ski hotspring soak, we went to Hakuginso, a short 10 minute drive away.

“Ryounkaku Onsen’s pools are always a bit tepid,” insisted Alex and Simon. 

When we arrived at Hakuginso, I was taken aback at how full the massive carpark was. The place was crawling with skiers, winter hikers, winter hikers with taboggans…it was really quite amazing. Almost a festival atmosphere. It was the busiest I’d ever seen it.

And now, on Sundays, they have a coffee van outside the onsen.

Comments | Queries | Reports

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

2 thoughts on “Ansei Crater (Kamihoro Valley)”

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.

See More Like this

Printable Ansei Crater Topomap


Download may take some time

Hokkaido Wilds Foundation

We’ve got affiliate links on to help fund the Hokkaido Wilds foundation.

The Foundation gets a small commission on sales from affiliate links, but we only link to stuff we think is worth checking out for people keen on the outdoors in Hokkaido and Japan.

The Hokkaido Wilds Foundation is a fund where 100% of funds are donated to Hokkaido volunteer groups involved in sustainable, safe, and responsible access to the Hokkaido outdoors.

Learn more here


Filter by location

About Filters

REGION: The general mountain/geographical region the route is in.

BEST MONTH(S): Time of year a route is suited to visiting. Some pop all season, some are more limited.

DIFFICULTY: How strenuous a route is, and how technical it is. Full details here.

FREERIDE/SKITOUR: Very subjective, but is a route more-of-a-walk-than-a-ski or the other way around? Some routes are all about the screaming downhill (freeride), some are more about the hunt for a peak or nice forest (ski-tour). Some are in between. 

MAIN ASPECT: Which cardinal direction the primary consequential slope is facing, that you might encounter on the route. More details here.

ROUTE TAGS: An eclectic picking of other categories that routes might belong to.

SEARCH BY LOCATION: You can find routes near your current location – just click on the crosshairs (). You may need to give permission to to know your GPS location (don’t worry, we won’t track you). Or, type in a destination, such as Niseko or Sapporo or Asahikawa etc.

Please let us know how we can make it easier to narrow down your search. Contact Rob at with your suggestions.

Ansei Crater (Kamihoro Valley) Difficulty Rating





Vertical Gain



Time ascending















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.