Grand Som

The Grand Som is a mountain of the Chartreuse Mountains in the French Prealps, in Isère, France. It has a long ridge, unevenly sharp, overlooking the Petit Som (1,772m), the Col de la Ruchère northwest and the Grande Chartreuse monastery below the cliffs. The summit has a cross and two relief tables. It lies in the Parc Naturel Régional de la Chartreuse.

Grand Som
The Grand Som from the Charmant Som.
Highest point
Elevation	2,026 m (6,647 ft)
Prominence	887 m (2,910 ft)[1]
Coordinates	45°22′14″N 05°48′43″E
Geography
Grand Som Location in the Alps
Location	Isère, France
Parent range	Chartreuse Mountains

Caving

Many chasms are present on the massif: Trou Lisse à Combonne (−303 m), puits de l'Écho (−396 m), gouffre Roland (−481 m), gouffre de Mauvernay (−507 m), gouffre des Aures (−512 m), but the most important network is the puits Francis (1,565 m) or Réseau de Bovinant [fr] of 723 meters deep for 6,836 m of development. Discovered in July 1966 by the caving club of La Tronche (FLT), the siphon at (−688 m) was reached on August 23, 1967. Upper entries were then found.^[2]

View from the col de la Ruchère to the Petit Som (1,772 metres (5,814 ft), on the left) and the summit of the Grand Som (on the right).