Switzerland Oberaarsee South
Oberaarsee South Bike Climb - PJAMM Cycling

18.4
PDI
13.3 mi
DISTANCE
3,547 ft
GAINED
4.5 %
AVG. GRADE
FULL CLIMB STATS
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Page Contributor(s): Ard Oostra, Montreux, Switzerland; Helmuth Dekkers, Netherlands

INTRO

Oberaarsee South climbs 21.5 km (13.3 mi) from Obergesteln in the upper Goms valley of Valais, over the Grimsel Pass and out along a private panoramic road to the Oberaarsee dam, gaining 1,081 m (3,547 ft) at a 4.5% average. The road tops out near 2,398 m (7,866 ft) before a short drop to the dam at 2,311 m (7,581 ft). That average is watered down by a flat first 3 km (1.9 mi) and the descent at the end - once the road leaves the valley floor at Oberwald, most of the climbing to the Grimsel runs at 6-8%.

Important for 2026 and 2027: the Oberaar Panoramic Road was closed to the public for the entire 2026 season for construction work, and its operator, Grimselwelt, has announced it will stay closed for the whole 2027 season too, with the Berghaus Oberaar closed for renovation. Until it reopens, the ride ends at the Grimsel Pass (2,164 m / 7,100 ft).

When it is open, it is worth the wait. Our Ambassador Helmuth Dekkers rode it from his hotel in Obergesteln: hairpins lift you out of the Goms past the Furka steam railway to Gletsch, six more switchbacks climb to the Grimsel, and from the pass the narrow Oberaar road runs high above the Grimselsee with views of the Unteraar glacier. The final rise reveals the reservoir below, with the Oberaar glacier at its far end - in Helmuth's words, an impressive view.

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The first 3 km (1.9 mi), from Obergesteln to Oberwald, are essentially flat at under 1%. The climbing starts at Oberwald, and kilometers 4 through 7 run between 4.9% and 6.9% as the road leaves the valley.

The heart of the climb is kilometers 8 to 14, where nearly every kilometer sits between 7.1% and 7.9% as the road reaches Gletsch (about 1,757 m / 5,764 ft) and switchbacks up to the Grimsel Pass. Past the pass, the Oberaar road is gentler and rolling, mostly between 2.4% and 6.3%, up to its high point near 2,398 m (7,866 ft). It then drops about 0.9 km (0.6 mi) to the dam, so the finish is downhill and 122 m (399 ft) of descent is built into the route.

The steepest 500 m (0.3 mi) averages 9.1%, the steepest 1 km (0.6 mi) 8.7%, the steepest 2 km (1.2 mi) 8.0%, the steepest 5 km (3.1 mi) 7.7% and the steepest 10 km (6.2 mi) 7.0%.
Roadway: Paved the whole way. The Grimsel is a major, well-maintained Swiss pass road, but it is seasonal - it closed for the winter in October 2026, and recent openings have ranged from late May to mid-June (29 May in 2026, 28 May in 2025, 14 June in 2024), so check the pass status before an early-season trip. The Oberaar Panoramic Road is a narrow private road built in 1949 by Kraftwerke Oberhasli for the dam, with very good asphalt and a long drop on one side. It is normally open to the public from about late June to late October, but it was closed for all of 2026 and is announced as closed for the 2027 season for construction. Riders who tried it in 2026 found signs, tape and locked gates - respect them.

Traffic: The Goms valley road and the Grimsel carry real summer traffic - cars, tour buses and plenty of motorcycles - so early mornings are best. Low cloud at the pass can cut drivers' visibility badly; our Ambassador rode with lights and a high-visibility vest for that reason. When the Oberaar road is open, cars run on a timed one-way system (uphill on the hour, downhill on the half hour), and traffic is light.

Parking: Obergesteln is a small village, and staying there lets you ride out from your door, as Helmuth did. If you are driving in, Oberwald is 3 km (1.9 mi) up the road (see our Furka Pass (Obergoms) page for parking there). At the top, parking along the Oberaar road itself is not allowed; there is paid parking at the Oberaarsee and the Berghaus Oberaar when the road is open.
Provisions: Stock up in Obergesteln or Oberwald. Our Ambassador passed the Rhonequelle restaurant on the way up to Gletsch, and there are hotel restaurants at the Grimsel Pass, but there is nothing past the pass while the Berghaus Oberaar is closed.

Gear: The gradients are moderate for an Alpine climb of this height, so a compact crankset with a 28-tooth cog is plenty. The bigger issue is weather: you finish well above 2,300 m (7,546 ft), the wind along the Grimselsee is cold even in summer, and cloud can roll in fast. Pack a windproof jacket and gloves for the descent, and front and rear lights for the pass.
Before heading out on any cycling adventure check out our Things to Bring on a Cycling Trip and use our interactive check list to ensure you don't forget anything.
Our Furka Pass (Obergoms) and Nufenen Pass West pages cover Oberwald, Gletsch, the Rhône Glacier and the villages down the Goms, so here is what is particular to this route.

Obergesteln, the start, is unusual for the Upper Valais: after a fire destroyed almost the whole village in 1868, the cantonal government allowed it to be rebuilt only in stone, so it lacks the dark larch-wood houses typical of the Goms. In the Middle Ages it was a customs post on the route from Bern to northern Italy.

At the Grimsel Pass, the small Totensee lake sits right beside the road, and from the start of the Oberaar road you look down on the Grimsel Hospiz on its island-like perch in the Grimselsee. While the road is closed, the Oberaarbahn cable car runs from the Hotel Grimsel Hospiz up to the Oberaar dam (26 June to 3 October in 2027), so you can still see the lake and glacier on a rest day. The summit is high and exposed, so check current conditions before you go with our Weather tool.

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CLIMB SUMMARY

Cycling Oberaarsee

Ride 21.5 kilometers gaining 1,078 meters at 4.5% (122 meters of descent)

This is a typically scenic Swiss Alps climb to Oberaarsee, a hydroelectric dam in the bike climbing hot spot of Grimsel.  There roughly 20 spectacular climbs in a 30 kilometer radius of Grimsel, including 4 Top World Bike Climbs.

Climb summary by PJAMM Ambassador Helmuth Dekkers, Netherlands.

Well, the most demanding side for the Grimselpass is the northern side from Innertkirchen.  It's 32.6km of cycling to gain 1675m which results in an average of 5.1 %. But as the weather predictions were not so good I did not dare to take the risk to cycle that side as I first had to drive 42km by car via the Grimselpass to Innertkirchen. The waitress in the hotel I stayed in Obergesteln told me that I had to be careful as the low hanging clouds can make it very dangerous for cyclists at the pass as motorcyclists and car drivers don't have a good vision and she had seen plenty of accidents during the 6 years she worked for the hotel next to the pass. Second reason is that I really have grown fond of the road from Obergesteln that takes you out of the Goms valley and up to Gletsch and the road that follows 🙂.

Scenes along the climb.

Bottom center photo:  Furka Steam Railway is a heritage railway operated in the area

So I started at the hotel and cycled 3km from Obergesteln to Obergoms which are fairly flat. After that the road goes up via 2 lovely hairpins (I love hairpins) and crosses the Dampfbahn Furka Bergstrecke which is a railroad track on which a steam (dampf) engine is running to take passengers from Oberwald to Realp. Shortly after you pass the Rhonequelle restaurant. And 1km further you'll pass through a very short tunnel. You can see ahead the road going up from Gletsch to the Grimselpass with numerous hairpins 🙂 But the clouds were hanging low and I did not see all the hairpins. Hmm, not sure if I would then cycle up to the pass itself.

With the warning of the waitress in the back of my mind I wore a fluorescent vest and had brought 2 tail lights and a front light too. When I turned them on I looked like a Christmas tree 🙂 But, better safe than sorry. And in the Goms valley the view was good. No need for the lights. Two hairpins take you higher up out of the valley and you can see the tunnel exit with wooden doors from the Furka Bergbahn below. The road sweeps to the right and then via another hairpin turn you reach Gletsch. When the weather  permits you can see  the road up to the Furkapass ahead. But to get to the Grimselpass one has to turn left to go up via a broad road with 6 hairpin turns. While making my way up I see here and there some blue sky and even the sun was peeking through the clouds. The clouds had lifted 🙂 and I could cycle with a clear view to the Grimselpass. Nice!

Next to the Grimselpass is the Totensee (Sea of the dead as soldiers were once driven into the lake to drown) . But we are not there yet. As it is possible to cycle from the Grimselpass on to the Oberaarsee. At start of the turnoff one can see the Hospice lying on its isle in the Grimselsee and the road leading down to Innertkirchen. The narrow road first goes up for 1km at 8% and then goes down again. Personally I don't like this as the height I gained is lost and for sure must be gained again. But the road is worth cycling as it runs along the Grimselsee and offers beautiful views on the lake itself, the surrounding mountains and the Unteraarglacier. The wind was chilling though. But as after the downhill it's 3.8km up again at a moderate 5% on average I got warm again.

Oberaar Reservoir

At the top you can see below the dam of the Oberaar reservoir and at the far end of the reservoir you can see the Oberaar glacier. It's an impressive view! I went down the short (920m) steep (9%) road to the dam. But the view  does not get better. It's just I wanted to cycle the road until the end. I felt very happy and fortunate that the weather was good enough to have cycled the beautiful road out of the Goms valley and then up via the hairpin turns to the Grimsel pass and on to the Oberaarsee. 

Oberaargletscher

Helmuth at Grimsel Pass about 6 km from the finish