Tour du Val d’Hérens: Thyon – Grande Dixence (stage 1)

Grande Dixence


The first stage of the Tour du Val d’Hérens is a panoramic high-level hike with a dramatic backdrop: glacier-draped peaks and Europe’s tallest dam.




15.95 km


5:00 h


The first leg of the 5-stage Tour du Val d’Hérens actually leads along a side valley: the Val d’Hérémence. The entire stage lies above 2,000 m, making for spectacular views of the valley, the mighty Grande Dixence dam and the snow-capped summits beyond.

The trail follows a scenic route along the valley’s western flank, threading through alpine pastures and a natural gem: Les Gouilles d’Essertze. These tranquil ponds are set among peat bogs more than 13,000 years old; info panels showcase the local wildlife. This makes an ideal picnic site – alternatively stop for refreshments at the Cabane d’Essertze, soon afterwards.

As the walk progresses, the sight of the finish point becomes ever more dramatic. The Grande Dixence is the world’s tallest gravity dam: 285 m tall, with a base 200 m wide and weighing some 15 million tons – more than the Great Pyramid of Giza. Its reservoir, the Lac des Dix, is the largest in Switzerland, and can hold 400 billion litres of water.

The dam forms the heart of a vast complex that is more impressive still. About 100 km of tunnels under the mountains collect meltwater from 35 Valais glaciers for storage in an interconnected group of reservoirs. The pioneering complex also includes 4 pumping stations and 3 power stations with a total output of 2,000 MW. One of these power stations alone holds 3 world records, including the greatest drop height (1,883 m). Taken as a whole, Switzerland’s largest hydroelectric plant accounts for 20% of the country’s energy storage capacity, generating enough electricity to power the equivalent of 500,000 homes.

Visitor facilities at the dam include an information centre (free admission), guided tours, a restaurant and a cable car to the crest.



  • High panoramic trail – spectacular views all along
  • Les Gouilles d’Essertze – idyllic group of alpine ponds
  • Grande Dixence – Switzerland’s tallest dam

Turn-by-turn directions

From Thyon, the trail leads south, traversing the flank of the mountain before climbing more steeply up to a spur overlooking the Gouilles d’Essertze. The path threads between the ponds and peat bogs before dropping down to the Cabane d’Essertze, a panoramic stop for refreshments. From here, the trail continues southwards up the Val d’Hérémence, roughly mid-level between the valley floor and the 3,000-metre summits on the right-hand side. The walk finishes at the top of the Grand Dixence dam.

It is also possible to start the walk at Les Collons, about 330 vertical metres below Thyon; allow about an hour for the additional climb.

At Grande Dixence, the hotel, restaurant, visitor centre and bus stop are located at the foot of the dam. Ride up to the crest by cable car, or allow about 45 minutes to walk up.

Alternative overnight accommodation option for hikers tackling stage 2 of the Tour du Val d’Hérens: the Cabane de Prafleuri (about 1 h 30 min on foot from the crest of the dam).


Thyon (2103m)


Grande Dixence (2149m)

Author's recommendation

Call in at the Grande Dixence visitor centre and book a “sound and light” tour inside the dam, daily from mid-June to late September.

Technical information












Best time of the year

  • Jan
  • Feb
  • Mar
  • Apr
  • May
  • Jun
  • Jul
  • Aug
  • Sep
  • Oct
  • Nov
  • Dec


  • Linear route
  • Multi-stage route
  • Scenic
  • Fauna
  • Refreshment stops available
  • Flora
Getting there

Public transport

Train to Sion, then postal bus to Thyon 2000. At end of walk, postal bus from the Grande Dixence dam to Sion. Find full timetable information at sbb.ch. 


A9 motorway, exit 27 (Sion-Est), follow signs for Vex, then Les Collons/Thyon.


Parking available at Thyon 2000. To return here from Grande Dixence dam, take postal bus towards Sion, change at road junction near Vex (bus stop «Vex – bifurcation d’Hérémence»). Alternatively, to reduce driving time, park lower down the valley – e.g. at Vex – and travel by postal bus to the start of the walk and back from the finish.


We recommend: 

  • good footwear
  • clothing suitable for the weather: always carry a waterproof jacket
  • hat or cap
  • sunscreen
  • bottle for water
  • picnic
  • camera
  • binoculars (optional)
  • hiking poles (optional)
  • printout of this hike (click «Print» icon, to download)  

For certain walks:

  • Swimwear

Safety information

Use of the trails and the information on this website is at hikers’ own risk. Local conditions may entail changes to routes. Valais/Wallis Promotion accepts no liability for the accuracy and completeness of information on this website.

For all hikes:

  • Bring a map. Download full description of this route including large-scale map by clicking on «Print» icon, top right of this page.
  • Use marked trails only, and observe all signposting – for your own safety, to safeguard grazing animals and to avoid disturbing wildlife.
  • Close gates after passing through.
  • Please be considerate to other trail users, and to the plants and animals.
  • Do not leave any waste in nature.

For mountain hikes:

  • Take extra care protecting yourself from the sun at altitude. UV radiation can be exceptionally strong, even in cloudy weather.
  • Plan hike carefully: take into consideration fitness level of each participant, weather forecast and season.
  • Weather conditions can change quickly in the mountains, without warning. Appropriate clothing is therefore essential, along with adequate supplies of food and water. In uncertain weather, turn back in good time.

For high-altitude hikes:

  • Inform others of the route you plan to take. Whenever possible, avoid going alone.
  • Do not venture onto glaciers without a mountain guide.
  • Take note of the warning signs that point out the constant danger in river beds and along watercourses below dams and reservoirs: water levels may rise rapidly without warning.

Additional information

More information about the destination: 


The tourist offices in Val d'Hérens have got brochures and information material about hiking in the region.


SwissTopo maps 1:25’000: 1306 Sion / 1326 Rosablanche


This activity is brought to you by Valais/Wallis Promotion