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Dent de Crolles

Report by Chris Jewell

Four of the youngest members of the BEC, including two of the most recently joined members went to the Dent de Crolles for the long Easter weekend and completed the Trou Glaz to Guiers Mort traverse. (Chris Jewell, Rich Bayfield, Rich Beer and Charlotte Harris)

Having recently become a full tax-paying member of society (i.e. not a student) I have had to face the realities of 22 days leave a year! Due to this the idea of doing long weekend pull-through trips in some of the classic European caves appealed.


I knew Easter would be a bit early for high Alpine caving because of the snow. However some people recommended the Dent de Crolles as the Trou Glaz is a ‘big yogi bear entrance near the path and won’t be snow plugged’ I did a bit of my own research and was led to believe that the snow would probably have gone so we booked our flights and crossed our fingers.

Due to the time of year none of the usual campsites were open but I managed to find a site a bit further away which also had Chalets. The “Balcon Chartreuse” is in Mirabel les Eschelles, about 40min drive away from the caving area.

We flew in to Lyon airport on Good Friday morning and picked up shopping for our stay on route to the campsite. By 1.30pm we were sat on the veranda of our chalet enjoying a proper French lunch in the beautiful sunshine. The accommodation was perfect for us, basically a large garden shed with a small upper floor for three mattresses, a small bathroom with shower and another separate bedroom. The rest of the space was for living, cooking and eating, with a dining table and all the cooking facilities we needed.

We had decided early on that we wanted indoor self-catering accommodation. It saves weight on the plane, as you don’t need tents, sleeping bags, stoves, pans etc. Also at this time of year when the weather is unpredictable coming back to a nice warm dry hut is great and finally when doing a long weekend like this it is very easy to keep unsociable hours – i.e. back too late to go to the restaurant. So coming back to a tent at midnight in the rain to start cooking didn’t appeal.

The Chalet was also pretty cheap, costing only 60E a night for everyone – so roughly £10 a head per night. Plus when you have somewhere decent to eat and drink there is less temptation to head for the nearest restaurant/bar so saving more money overall.   

On Friday afternoon we packed up our kit and headed for St. Pierre de Chartreuse, the village closest to the bottom entrance of Guiers Mort. We parked in a car park at the end of the road by the foot of the mountain and got changed in the sunshine. Although there was a lot of snow on the path the sun was hot and we all worked up a sweat on the walk. After one wrong turn we realised we had to follow the track with the large yellow cross and were soon climbing towards the entrance.

(Park in the car park, follow path until big corner/clearing) where bridge crosses river and where waterfall comes over cliff far above (you will know when you are here). Continue on the main path past here until you see a right hand turn which climbs steeply. Very obvious path and clear junction with a yellow X on a tree stump. Follow this until you reach a small stone building out of which a stream emerges. Stepping over the stream the path becomes a tiny track zigzagging up the hill. After a short distance it rejoins another larger path and 50m ahead is a sign post for the source of Guiers Mort, with a path which goes off to the left. Follow this zig zagging path up to the entrance.) 

The entrance is a massive resurgence with traverse lines coming out on both sides to reach the cliff. There was plenty of snow about but none of it prevented us getting to the cave and we were soon heading off down the entrance passage.

The stream emerges mostly from a hole on the right but the way on is down the larger dryer tunnel, which soon reaches a large chamber with the obvious way on the right. However at the back of the chamber a small draughting hole can be entered which takes you towards the bottom of Puits Pierre. Follow the small passage ahead, traversing over a pit and then afterwards climbing up to the left. If in doubt follow the worn, obvious draughting way. When the crawl emerges turn left and then take the next left to find the bottom of Puits Pierre.  

Fortunately for us the pitch was rigged and judging by the quality of rope and the fact there are several re-belays it probably always is. Up the rope the passage is large at first then turns into an uphill, slippery crawl at the end of which the way on is right (left is marked with a line of stones).

Then we followed the large obvious passages, over the impressive pitch Elizabeth, and past numerous side passages until eventually reaching the bottom of Puits Banane. Banane was also rigged and similarly to Pierre, I suspect it normally is. The navigation through this section is fairly easy once you’ve done it once but there are many passages to confuse and tempt you and we were happy to have a survey from Mad Phil and descriptions from the internet – both of which I’d laminated beforehand.

Banane leads to a high level passage, interrupted half way by a short traverse. Not long after this we reached the head of the cascade Rocheuse where we checked the pitch was rigged. Happy to see the rope the others opened our snack supply whilst I dropped part way down the pitch to check it looked ok. Satisfied with the pitch we turned around and headed out with the knowledge that everything was in place for the through trip. Most of all we were surprised at how quickly we’d reached this point in the cave. We’d crossed two and a half of the four survey sheets and it only took about and hour and a half to get out from this point. 

We were back at the hut at about 11.45 for a quick dinner and then straight into bed for a good night sleep before the big trip.

When we woke up on Saturday the rain was pouring down. We knew this wouldn’t affect the trip – which is pretty much dry the whole way but it would make the hike up to Trou Glaz miserable. Hopeful that that weather would be better closer to the caves we set off anyway and fortunately by the time we reached the car park the rain had stopped.

There are several routes to the Trou Glaz entrance. The shortest route is to drive to the Col du Coq. However as didn’t have a second car, our only option was to park by the bottom entrance and walk up. Apparently there is a short but scary route from the Guiers Mort entrance across and up the cliffs. The descriptions we read were of people doing this in the summer so given the weather conditions and the snow at this height we opted for the long way round. This means walking first to the Col des Ayes (about an hour and a half walk to the area just above the Col du Coq) then across the slopes to the entrance. This was all on a proper, heavily marked foot path so we were confident of having no problems despite expecting to be traipsing through snow most of the way.

The lower part of the path was fairly steep and over snow it was hard work. However the path was large and well protected and we were happy to trudge upwards. When we reached the Col des Ayes though things took a different turn. The path turned into a narrow and exposed ledge, which is probably quite fun in the summer. However with snow covering the mountainside this became pretty treacherous. It soon got even worse as the path completely disappeared under the snow and we had to cut steps across 45 degree snow slopes with nothing but a long drop below. It took us over two hours and forty minutes instead of about forty minutes to cover the distance to the Trou Glaz entrance and we were all relieved to reach the cave. Standing in the entrance we all knew the hardest bit of the day was finished – just a quick caving trip to do now.

The entrance splits in two after about a hundred meters. We went to the left and followed the passage until we found a 45 degree bedding plane which led to a squeeze up into a chamber. Ducking under the left-hand wall the passage rose and we walked about twenty metres until up on the right we spotted the ledge leading to the lantern pitches. This is easy to miss as there are plenty of signs pointing straight on and it looks like the obvious route. Straight ahead is actually a long bypass to the lantern pitches so perhaps gets just as much traffic as them.  

The pitches were covered in ice, which gave me a little concern. Namely that we would find an iced up squeeze! We dropped down the first two pitches quickly and at the bottom of the second I wandered off to find the next pitch head. The entire belay was covered with ice but fortunately there was another anchor on the left hand wall. I knew that at the bottom of this pitch we would find the pitch bypass passage back up to the entrance so as long as we could get down and reach the passage it would be ok. To be safe I told the others to keep the top two pitches rigged whilst I dropped the third and checked for a way through. Fortunately there were no iced up squeezes and we pulled down and headed for the fourth lantern pitch, five minutes ahead.

The fourth pitch is an impressive drop in the floor of a train tunnel sized passage – for some reason the passage has just decided to continue 12m lower down in exactly the same vein.

Shortly after this we traversed half way over a pit and climbed round to the right to find the big 36m pitch. This sounded wet but all the water was out of the way at the bottom and we dropped down easily. From here there are two short pitches to reach the meandering stream way and another slightly longer one before the puits de l’Arche where you abseil all of about 4m to a traverse line leading straight over. This takes you immediately to the head of the 11m puits des Maichanceux, followed by another of the same (P. du Biouvac). Marching up the passage here you soon enter Les Champs Elysees, which leads to the galerie des Champignons. Full of ‘pop corn’ type formations (or mushroom like as the name suggests) this is where the end of the Rocheuse rope is found. Like Puits Pierre and Banane it appears this is always rigged – at least it is not possible to rig it as a pull through! To find the bottom of the rope climb straight up where the worn section is and a muddy rope can be found against the rock. 

Once at the top of Rocheuse it was just a matter of repeating our exit of the previous day. The only difference was the amount of water now emerging from the cave due to the rain and snow melt. We were back at car at 11.40 and soon in the chalet stuffing our faces and drinking beer, feeling suitably happy with ourselves.

To see more photos of the above trip please take a look at photos taken by both Rich’s