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The Col de la Croix de Fer

Toponymy

Le Col de la Croix de Fer (FR-73-2064a) owes its current name to the imposing iron cross at its summit.

This cross has been vandalised in 2016 then rebuilt by the commune of Saint-Sorlin d'Arves.

In the past, the pass was called Col d'Olle. The source of the eponymous torrent is nearby.

Geographical location

Massifs

The pass lies on the boundary between the Alpine massifs of the Grandes Rousses (to the south), the Arves (to the east) and the Belledonne mountain range (further west).  

Geology

The Col du Glandon and the Col de la Croix de Fer are geographically very close, less than 3 km apart.

The Col de la Croix-de-Fer is geologically part of the massif of the Grandes Rousses. This is part of the vast crystalline region that includes the Mercantour, Les Écrins, Oisans, Belledonne and Mont-Blanc massifs.

The rocks that make up the pass are volcanic tuffs from a volcanic outpouring dating from the Carboniferous period (around 300 million years ago), the result of the collision of tectonic plates during the uprising of the Alps. It is also possible to observe "roche moutonnées" or "whaleback rocks". These are outcropping rocks that bear the scars of a glacier rubbing against their surface, striating and polishing them.

Readers interested in this subject should refer to the comprehensive article by geol-alp.com 

Hydrography

West side (Isère side) Eau d'Olle valley.
L'eau d'Olle is a tributary of the Romanche, which rises near the Col de la Croix de Fer.

East and north-facing slopes (Savoie side) : the Arvan valley.
It is also known as the Vallée des Arves.
The Arvan is a tributary of the Arc at Saint Jean de Maurienne.

Both slopes are part of the Isère basin.

Access

Isère side

Access is shared with the Col du Glandon as far as the D926 / D927 junction (alt. 1907 m), 200 m from the Col du Glandon and 2.7 km from the Col de la Croix de Fer.

The D526 leaves Rochetaillée (32.5 km away, alt. 711 m), crosses Allemond (30 km away), passes over the Verneys dam and runs alongside the lake (left bank), crosses the Rivier d'Allemond (18 km away - alt. 1264 m), near the Grand'Maison dam (9 km away - alt. 1720 m) then runs alongside the lake on the right bank. It becomes the D926 as it crosses the Rieu Claret (4 km away, on the Isère / Savoie border, alt. 1773 m) before joining the junction with the D927 towards the Col de la Croix de Fer.

Savoie side

From Saint Jean de Maurienne (29 km away - alt. 570 m), via the D926 Pont de Belleville (14km away - alt. 1228m), Saint Sorlin d'Arves (10km away - 1400m).

Three tunnels (96, 178 and 503 m - well lit) located between 17.5 and 16 km from the summit of the col.

Via the Glandon passthe D927 gives access to the Col du Glandon (FR-73-1924) from the Maurienne (Saint-Etienne de Cuines 21 km away - alt. 450 m) via Saint-Colomban-des-Villards (10 km from the pass - alt. 1100 m).

From the Col du Glandon, take the short descent (200m) to the junction (alt. 1907m) with the D926 from Allemont and the Lac de Grand'Maison. The Col de la Croix de Fer is then 2.7 km away.

Modification of access

Isère side

The road was first built to the Col du Glandon in 1898. The extension to the Col de la Croix de Fer was inaugurated on 14 July 1912.

At the end of the XX^th century two changes:

• The route was changed with the construction of the Grand-Maison dam from 1978 to 1985. The road slightly overhangs the lake (around fifty metres) before descending slightly towards the Eau d'Olle.
• On 23 April 1989, a Landslide from Pic Bunard  (300 to 400 m³ of rocks) swept away the road (right bank of the Eau d'Olle) above the Rivier d'Allemond at the Maupas waterfall. The road was rebuilt on the left bank over 2 km, with a descent (62 m in 600 m) to cross the torrent and then a fairly steep ascent (11% for the first kilometre). The old road can still be seen along the right bank of the mountain. (It was a year with Marmotte and BRA. A new road was built in 2 months! A miracle of decision).

Savoie side

For several centuries, only a mule track led to the pass.
 It was turned into a road in 1900 from Saint-Sorlin-d'Arves to the pass (then extended to the Col du Glandon in 1912).  

What to see - tourism 

Isère side (shared with Col du Glandon)

La Grand'Maison power station is a Pumped Energy Transfer Station (PETS).

A higher restraint (Grand'Maison lake(1,695 m) is connected by penstocks to a lower basin, the Le Verney reservoir, 900 m below the level of the power station (Lac du Verney725 m, 15 million m³ of water). During periods of high consumption, the power station turbines water from the upper reservoir. The water then flows into the downstream reservoir. During off-peak periods, mainly at night and weekends, water from the lower reservoir is pumped to the upper reservoir.

In this way, the system can store energy and respond quickly to peak demand.

The most powerful dam in Europe, it produces the equivalent of 2 old-generation nuclear reactors.

Le EDF Hydrélec Museum between the road and the Lac du Verney has been awarded the Museum of France and presents unique collections from the Alpine Arc dating from the 19th century to the present day.^e century and xx^e century. A scenographic tour pays tribute to the scientists, engineers, technicians and labourers involved in the creation of hydroelectric power stations and dams.

Savoie side

Visit carrefour d'Entraigues12.5 km from the pass, you can admire the wooden sculpture of the guide Guille, a native of Entraigues and a pioneer in the conquest of the Aiguilles d'Arves and the Étendard).

A Saint Sorlin d'Arves : l'Saint-Saturnin Church (built in 1603)

At the pass

Two orientation tables:

• One to the east of the pass, facing the Arvan valley and the Aiguilles d'Arves mountains
• The other to the west, looking towards the upper reaches of the Eau d'Olle, the Col du Glandon and the Belledonne mountain range.

Above the collar

Three Lakes Circuit to the Étendard refuge, Lac Bramant and Lac Blanc

Administrative status

Currently

Both sides of the pass are in the Savoie department (Commune de Saint-Sorlin-d'Arves.

The Isère / Savoie boundary is located on the Isère side at the Pont du Rieu Claret (1730 m), 6.3 km from the pass.

History

Why isn't the Isère / Savoie boundary on the Arc / Isère LPE? (i.e. the Croix de Fer and Glandon passes)

According to "oisans.com

Until 1860, the Sabot pass marked the border between France and Savoie. Vaujany, on the route des cols, was then equipped with a border office to protect the province of Dauphiné. ... / ... Where the Grand'Maison reservoir now extends, in the past, vast alpine pastures were shared between the French and Savoyards. The Grand'Maison was a large building used to house shepherds. Information completed by " Isère-Tourisme " Behind the Col du Sabot was a border post, some of whose ruins still exist. 

ChatGPT completes this information (without citing sources):

"The region around the Croix de Fer and Glandon passes is an area of mountain pastures where Savoyard and Dauphinois farmers have practised agriculture for centuries. The inhabitants on both sides of the mountain had a close relationship and often shared pastures and farmland.

When the border was defined as part of the Treaty of Turin in 1860, it was important to minimise disruption to the local population. Fixing the border on the Rieu Claret, a clearly identifiable watercourse, made it possible to maintain the traditional use rights of farmers on both sides of the border".

Cycling and cycle tourism

Tour de France

The Tour de France climbed this pass for the first time in 1947.

Critérium du Dauphiné

The pass was on the programme for the 2008, 2009 and 2011 editions. It was the finish of the 7^e stage of the Critérium du Dauphiné 2023 won by Jonas Vingegaard, who thus secured his victory in this edition.

It is the highest finish in the history of the Critérium du Dauphiné.

BRA

The ARO has been using the Col de la Croix de Fer since its creation in 1936.

• On the Savoie side from 1936 to 1945
• Alternating between Isère and Savoie after 1945
• On the Isère side since 2015

Marmot

From its inception in 1982 to 1999, the "La Marmotte" cyclosportive race was run over the Col de La Croix de Fer, before moving on to the Col du Glandon.

In 2023, the Glandon was no longer on the programme, and the route took in the Col de la Croix de Fer (and the Col du Mollard).

Profile

There are many profiles of the Col de la Croix de Fer on the internet. The percentages given are quite variable.

The best way to do this is to plot your route on Openrunner and click on "see altimeter profile", as shown here between Allemond (Isère) and Saint-Jean-de-Maurienne (Savoie):

A detailed profile of the northern slope shows the difficulty created by the landslide in 1989 and the new road on the left bank of the Eau d'Olle (km 12).

And, finally, a few images about the Croix de Fer and du Glandon

An article by Gérard Galland (and Bernard Giraudeau for the geology section)