Grotte - Exsurgence de l'Avancas - by Jarvist Frost

Initial Descent

A 'nice dive' and 'not a toilet'. Well.


Finding it was easy enough - left outside the campsite, past the beautiful stone bridge and first right just beyond, admire the strange deserted country mansion with 'princess bedroom' towers at the four corners, and past the parking area with the exposed mud bands. 'Risk of innodation' say the signs, and a small concrete ford built into the road - upstream here is the cave. Grass parking 20m beyond on the right, and a path leading up to the (dry) river bank, terminating after circa. 30m total from the road in an obvious cave entrance & flood resurgence. I carried my gear up in flipflops, soon realising that I'd left my wetsuit (& fins, regulators) back in the campsite. I return to find my cylinders magically transported to the sump - perfect timing.

The carry into the cave is pleasant, perhaps 50m of passage. Entrance is a boulder slope, constantly collapsing but negotiable with care. Cave passage is mainly walking height, with a spot of stooping. Plenty of space to get kitted up just before the sump, which was for us a pool about 3m across and 7m along.

Initial Junction at 6 metres depth

Silt stirred by first diver

We followed the SRT line down into the sump to achieve 6m depth at about 12m from the start. Here there was a branch, SRT line doubles under the roof to the left, and thin white line beckons onwards. Tim pegged the line out and stood aside for me to pass onto the thin line. The cave is indeed beautiful, and the passage fine. However, it's also extremely silty - there's puddles of ~5cm deep incredibly fine brown stuff everywhere.

Entering tight phreatic at ~40m line length

Pristine view of first diver at ~60m line

In this early section I saw some curious insects - the first had the cross section of a cuttlefish, opaque white and perhaps 2cm along. Another was some form of shrimp, but large and seeming to impersonate a seahorse, with flashes of orange and purple in the translucent body.

The passage was spacious to begin with, but soon passed via angular cross rifts into narrow phreatic crawls with aesthetically pleasing but very sharp and catchy veins of calcite. The 50m point is marked by a labelled arrow. The phreatics would be a low crawl in a dry cave, and there is precious little that can be done to avoid stirring the vis. There is not room for a frog kick, and best seemed to be pushing with fingers off the relatively clean wall.

Shortly before surfacing in airbell - pristine visibility

Start of ascent into airbell, typical of transition between phreatic and cross rifts

At a cross-rift phreatic elbow, Tim caught up with me and signalled to overtake with the camera. Now I got to enjoy the poor vis! I really have no idea about the further passage, other than the film footage Tim recorded. It ends in a cross rift that takes you up to an airbell and an easy lurch over some wedged blocks.

Tim and I were here with approx. 7 mins dive time. Andras was notable by his complete absence. After ten minutes we decided that though we were almost totally certain he was OK & had backed off in the poor vis, if there was a problem (he was in a dry suit, the cave was tight and snagey), we'd rather try to sort it with large gas margins rather than go further first.

Typical sound belay

Surfacing in the first airbell (90m in)

I followed Tim out, I could mainly sense his presence (and slow down a bit) not by seeing him, but by noticing the vortices his fin strokes had left in the brown swirls. Vis was below 10cm in sections (mainly the phreas tunnels). At one point I could not read my long-hosed gauge (the short one I could not even get close enough to see). The line was fine to follow out in such conditions, but worryingly thin.

Conditions on dive out

Back at S1, Andras was present & fully dekitted, having decided to back out after having lost contact with us, finding himself in passage too small to turn in with no vis.

Tim and I decided to dive down the SRT rope lined route, which we believed would gain a dry route running parallel to S1. The SRT line branches off at 6m, seems to go under a rock obstruction or two and then directly surface in a small chamber with a V-shaped cross section and absolutely choked with knee-deep mud. The primary belay was via a loop of climbing rope to a piton hammered into the central fissure. There were pieces of a rusted-apart electron ladder near the top of the chamber, the climb up to the right (+3m) into the passage was not attempted as the 45-degree inclined rock shelves were smeared with mud.

Cleaning mud from regulators before diving out from 'SRT line' sump

We dived out in essentially zero vis conditions. The SRT line was comforting in its thickness, though at the junction the thin line leading off forms a bit of a trip hazard. Via a short interlude posing for photos, we exited for tea and medals. Carrying cylinders directly out still attached to harness was found to be fine.

The entirity of what was seen on the dive out of the 'SRT line' sump

Certainly one to return to, though solo diving and leaving the first sump to settle a little for the return would be more ideal. See CDG dive report C.D.Westlake 14-8-11 for a description of the bits beyond.

Jarv