Grenoble to Briançon (D1091) closed

[briantrumpet]

ERDF (the infrastructure part of EDF) which manages the lake, says no. The water level has already been reduced substantially because of some issues with the dam, but the wave resulting from the slippage has been forecast to be 2-4m high, so no threat, according to them.

The latest is that they are considering draining the reservoir in order to try to make the slippage more likely. http://www.dici.fr/actu/2015/07/08/tunnel-chambon-place-purge-hydraulique-616146

... I think I'll not be holding my breath for the time being.

 

[Blue Hills]

To sve me struggling with the french mr trumpet, how does the draining make the fall more likely?

As you can maybe tell such matters aren't my strong point. But i am interested.

 

[psmiffy]

Removes some support for the toe of the slip plus in the short term the slip mass will be effectively heavier - I still think it will trundle down slowly or maybe even at some point stop

 

[briantrumpet]

Removes some support for the toe of the slip plus in the short term the slip mass will be effectively heavier - I still think it will trundle down slowly or maybe even at some point stop

That latter possibility would be the absolute worst outcome - I think if that happened they'd have to resort to the explosive option - until the 2 million tonnes of stuff has come down they won't be able to start work on reconnecting the communities. It's being brought up at national level, as it is killing a great part of the local tourist industry, as well as disrupting people's work and schooling.

 

[whosadam]

I've spent a bit of time around this area through the winters and I want to cycle around here next summer.

Has anyone cycled the long route over the col de croix to San Martin D-Arc then down to south coming out to the east of La Grave.
I've not seen the road but i can imagine its stunning.
The route we have planned doesn't go over this (but I could be persuaded...)

Definitely a blow for the towns that end of the road - The silver lining in all this is that the skiers have a quieter mountain to play on.

 

[psmiffy]

I think if that happened they'd have to resort to the explosive option

The French have a lot of experience bringing down snow in the Alps with explosives but this is a totally different ball game - much more friction holding it up and now estimated at 1M cu.m. - a small matter of 2MT to mobilise - I have not read anywhere on the origon/cause (may be a pre-existing glacial slip) of the slip but looking at the pictures the backscar does not seem to be onto the intact rock - there might be another one behind it

 

[briantrumpet]

For comparison, here's what happens when gravity makes bits of mountains fall off:

This is Le Claps, near Luc-en-Diois. Quite an interesting history (try Google Translate if your French is rusty): https://fr.wikipedia.org/wiki/Claps - it crated a 300 hectare lake back in the 15th Century, which then became the focus of several conflicts, as lakes in limestone environments are highly prized. A slight irony that they are talking about draining another lake in order to help a landslip happen.

 

[briantrumpet]

Removes some support for the toe of the slip plus in the short term the slip mass will be effectively heavier - I still think it will trundle down slowly or maybe even at some point stop

Haha... now they are thinking about RAISING the water level by 3.5m... do I hear collective head-scratching and shoulder shrugging? http://www.ledauphine.com/isere-sud...cture-va-tester-une-montee-du-niveau-de-l-eau

 

[ColinJ]

I think they should tie a safety rope round the waist of that person in the red coat and then ask them to jump up and down vigorously until the vibrations make the landslide take place!

 

[psmiffy]

It doesnt say in the article - but I assume it has stopped? I assume the water level is the only thing that they have that they can play with - they are not a very patient lot

(the water level is nice and low now - there was an Italian dam - Vujont - that a landslide caused a Tsunami in the late 1950s - overtopped with 2000 killed)

 

[psmiffy]

I assume that nothing has happened

For over one hundred days already, the landslide is delayed. Since the closure to traffic of the tunnel Chambon (Isère), threatened by the collapse of a mountain pan, on April 10, the village of La Grave (Hautes-Alpes) lives in slow motion, isolated from the rest of the region.

 

[briantrumpet]

I assume that nothing has happened

It's all still moving, but slowly. http://www.lemedia05.com/tag/tunnel-du-chambon/

 

[Ricey155]

Riding yesterday from huez, La sareene to mizeon they were blowing up parts up over the opposite side :-(

The long way round only for a while

 

[briantrumpet]

This is a rather good photo of the slipping chunk of hillside and tunnel:

There's even talk of opening the tunnel before the winter "as long as the work commences by mid-September"... though others are, er, doubtful. I'm guessing that caution will win out. http://www.lemedia05.com/2015/26284...solution-technique-pour-rouvrir-avant-lhiver/

 

[psmiffy]

I cannot see that the tunnel will ever be reopened - features like this can remain unstable but stable for thousands of years - I doubt they even know the full extent of the potential instability