Passage Du Fourneau
Take the forest road from les Pres and park at a right hand hairpin at 1230 meters altitude. The track is fairly smooth but some people prefer to park at the end of the metalled road at the left-hand hairpin just above les Pres although this adds another 20 minutes to the walk.
Follow the gated forest track towards the south. You will see a large rock on the left with orange markings indicating the route. After about 300 meters there is another rock with an orange arrow and the letter F marks the start of the path to the passage du Fourneau. Follow this path to the right, it climbs gently crossing another forest trail after 100 meters and joins the path from Pre Orcel after a further 400m. After this point it follows the contours for some time. An arrow indicates a small path heading directly up a ridge to the south-west. This path has occasional orange markings. The forest is fairly clear and it takes good eyes and concentration to keep to the path. Remember that it heads more or less straight up the slope except for a short traverse to the south as it exits the forest under the cliffs.
The exit from the forest
This traverse crosses some scree debris. The passage du Fourneau climbs a narrow and steep gorge with some short scrambles. The Fourneau is divided into two bowls both of which are crossed by cliffs and this provides the major difficulty for this route. The gorge exits into the south bowl, the path immediately traverses to the north-west into the north bowl via a small pass.
Looking down the gorge
There is a large cliff to our immediate right which stops us descending this bowl directly. This bowl is crossed by a series of rock steps, the path keeps to the right bank (looking down the mountain) before crossing back into the south bowl. This avoids a significant cliff band in the south bowl which is now to our left and would be a serious danger in poor visibility.
Take great care when descending as the orange markings and cairns are not always obvious from above. From here we climb directly up a gentle grass slope (cairns) at the top of which you scramble to the north-west before exiting the passage with a horizontal traverse to the south.
From the summit of the Fourneau it is possible to descend by the Pas de la Rousse or the Col de lAlpe. Allow about an hour to traverse to the col de lAlpe (orange markings), firstly because the path is crossed by rocks eroded by acidic rainwater (lapiaz) which makes quick walking difficult and secondly because you will want to take in the views from the ridgeline.
Views over the Chartreuse
You will notice many burnt tree stumps on the ridge. These are the remains of a fire that started during the heatwave of 2003. The fire was probably started by a lightning strike. Just before the Pas de la Rousse is the Burned Pine Loop (Sangle des Pins Brules? orange markings and cairn) described in Pascal Sombardiers excellent book: Chartreuse Inedit. This loop is a steep but walkable band situated just below the summit cliffs. Some of these loops travel a considerable distance and are the habitat of marmottes and chamois. It is not possible to descend into the valley via this loop or at least nor without a considerable abseil over cliffs.
|Summit||Passage du Fourneau|
|Distance||2.8km (one way|
|Maps||IGN Top 25 - 3333OT Massif De La Chartreuse Nord|
|GPS Waypoint||N45.3948, E 05.9116°|
|Markings||Orange - intermittent|
|Equipment||Good walking boots|
|Road Access||A41 -> le Touvet exit -> St Vincent de Mercuze -> Montalieu -> D282a -> D282 -> les Pres|
I had a couple of hours one hot and sunny June morning and decided to check out this secret route. Until recently it was not well marked and few people come this way. However some recent guide books of the Charteuse have made all these passages more popular.
The Cayman sees everything
This is not a route you would tackle in cloud or fog as route finding is somewhat complicated (okay you can download the GPS route) and there are some nasty drops. I decided to link the ascent of the Fourneau with the Pas de la Rousse which, in my opinion, is slightly more difficult. The traverse over to the Fourneau is quite long, as is the walk back to the Rousse but worth it for the strange Cayman shaped rock that looks out over the Gresivaudan valley.
Contributed by davidof on the 15th June 2006
Page last modified on September 13, 2006, at 08:54 PM