8 July 2015 update to the Tunnel du Chambon and the impact on the Tour de France.
The latest on the Tunnel du Chambon is that work on the tunnel has totally stopped, since they expect the side of the mountain above to fall at any moment. Small sections of rock have already fallen and some people are camped up high on the far side of the reservoir hoping to witness the collapse of the mountain. Access to the path on the far side is strictly closed and the ferry service has been stopped due to the fear of waves that would be caused by the rockfall. Local residence below the dam have been warned to keep doors and windows closed in the event of warning sirens, in the unlikely event that a wave could flow over the dam and flood villages downstream. A helicopter service has been put in place available to locals trapped on the far side in the case of emergencies.
The area of unstable rock is about25 – 30 meters deep and 600k to 1 million cubic metres. Since April it had been moving between 5 to 10 cm per day. More recently it been moving at 12 cm to 15 cm per day. Since 2nd July a section of 100k cubic tonnes has been moving at 25 cm per day which is looking like the first area to slide. Small sections of the mountainside have already started to slip into the reservoir.
As an impact of this road closure Stage 20 of the Tour de France on the 25th July between Modane and Alpe d’Huez no longer passes over the Col du Galibier, but via the Col de la Croix du Fer.
Many people booked into accommodation in La Grave or Briancon hoping to see the Tour de France on Alpe d’Huez, have been asking about the possibility to bypass the tunnel my mountain path or track. As mentioned before, then path along the other side of the reservoir is closed and this is being strictly enforced by local police. The quickest road route is via the Col du Galibier and the Col de la Croix du Fer. However there is a very long, but beautiful option above the tunnel via the Plateau de Emparis. This track is unpaved, generally used by walkers and mountain bikers and will take a long time, but is spectacular. Details of this route can be found via the following link under Tour du Plateau d’Emparis – itineraire 4.