The abandoned Tunnel du Mortier in France

Located in the Isère department in France, Tunnel du Mortier is an abandoned high mountain tunnel at an elevation of 1.370m (4,494ft) above sea level.

Tunnel du Mortier

Where is Tunnel du Mortier?

The tunnel is located in the Auvergne-Rhône-Alpes region, in the southeastern part of the country.

When was Tunnel du Mortier built?

There is a plaque by the North entrance of the tunnel saying it was constructed for the 1968 Winter Olympic Games of Grenoble, but according to the Autrans website there's been a tunnel since 1911 and 1968 was only an upgrade. The inauguration of this upgrade was on September, 30th, done by Louis Verger.

Is Tunnel du Mortier open?

The tunnel closed in 1992, after a rockfall destroyed the access road. On April, 20th, 1992, a breakdown, estimated in 20,000 m3, occurred below the top of the Buffe, collapsing the road and creating a zone of instability. The road was totally closed to traffic at the Buffe point. This collapse happened just 1 km far from another important collapse in 1971 (50 000 m3). As this road is of little importance and the possibility of another rockfall is very high the government decided not to repair the road. It was closed and is now used by hikers and mountain bikers. The damage to the road and the situation was so serious that no attempt has ever been made to restore the road. A forest track was developed in 2017 allowing limited use but for a short time since a new landslide during the winter of 2021-2022 closed access again.

Can you drive through Tunnel du Mortier?

Set high in the Vercors mountain range, the tunnel was built for two full lanes of traffic. It has no lights, and it's long enough, 500 meters, but lots of light pouring in from the ends on a clear day. The first maybe 100 meters are easy enough but the entire middle section can be pretty dark. Try to ride on the center as long as you don't look up at the far end. The light at the end of the tunnel will wreck your vision. There’s a real deathly risk on this tunnel. You can ride through the tunnel, but there is a rock slide that has cut off the road further down the climb. You need to be very careful to cross, but it can be done and you can then descend into the Vercors. The tunnel is passable, but you need to bring a light. It’s pretty long and obviously completely dark. The surface is smooth and devoid of obstacles and manholes. There are a few smaller rocks towards the Isere end, but by then it's lit enough to see.

How to reach Tunnel du Mortier?

The road to the tunnel is called D218. It’s a paved road, with narrow parts. On the southeastern side, the road is drivable to the tunnel. On the northwestern side, the road has collapsed completely and it’s impassable to cars. The road has steep parts, hitting a 12.0% of maximum gradient through some of the ramps.
Pic: webbenji