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Dent des Crolles

  • Author: TrailExplorer

Dent des Crolles

This walk, in the Hauts de Chartreuse nature reserve, goes via the Col des Ayes to the Trou Glaz, one of the largest underground tunnel systems in Europe. Via a number of secured passages it continues to the top of La Dent de Crolles from where you have a beautiful view of the Grésivaudan plain, the Belledone massif and sometimes the Mont Blanc massif.

Distance: 7.5 km

Time: 3h00.

Grade: Heavy.


Gps Track: Yes.

Route description: Yes.

Wheelchair: Not suitable.

Dog: Not allowed.

Height gain: 667 meters.

Trail: 100% unpaved.

Marking: Partly White-Red | GR9.

Hiking shoes recommended.


Le Trou du Glaz and Le Pas de l'Oeille.

This walk is for people who love a bit of adventure combined with beautiful surroundings. The route starts at the Col du Coq where you follow the GR9 via a beautiful forest path towards Col des Ayes. When you come out of the forest you immediately get a beautiful view of the Ayes plain. From the plain you start to ascend via a few hairpin bends, along the way you will come across the path that comes from the Pas de l'Oeille on the right. You follow the path on the left along the western flank. The path descends a little and you soon reach Le Trou du Glaz. Le Trou du Glaz is an entrance to one of the largest underground tunnel systems in Europe, almost 50 kilometers in total. Immediately after the Trou du Glaz you reach the first of a series of secured passages. You have to be careful here because the path is often slippery and slippery, but it never really becomes dangerous. A little further you have to go through a narrow passage through which broad-shouldered people have to pass sideways. After this series of spectacular sections, you quickly reach the plateau via two steep hairpin bends. Here you leave the GR9 and follow the path to the right towards the cross at the top of La Dent de Crolles. There are several Lapiaz (crevices worn by erosion) on the plain, so it is better not to undertake this walk if there are still snow fields! When you reach the cross at the top you will be treated to a beautiful view of the Grésivaudan plain and the Belledone massif. After enjoying the panorama, walk towards Pas de l'Oeille, which is located a hundred meters from the top in a westerly direction. Now we have to pay attention. The descent is steep and there is one secured passage. You now descend further via several hairpin bends until you reach the plain of Ayes. Then you return via the same forest path that you took on the way to the starting point.

Dent des Crolles

Download PDF for map and route description.

This walking route is not recommended for people with a fear of heights and you must exercise the necessary caution at the various secured passages.

Do not undertake when there are still snow fields.

Map & Poi's.