Grande Faille des Roches Blanches

Vast open-air separation fissure in the cliff, which has partially isolated a section of cliff 30 metres wide in the North (where the fault does not reach the cliff edge) and about ten metres wide in the South, over 200 m of length. The two walls are 1.5 to 6 or 8 m apart depending on the location, with several wedged blocks. The floor of the fault is always 2 to 4 m wide and, towards the end, the width increases to 6 or 7 m.

The floor can be reached either by starting from above with equipment, or directly by entering via the South end.

Descent via the North end: descent over mossy blocks with 5 to 6 m of elevation change (rope useful for the return), then progression along the gently sloping floor of the fault for about twenty metres; it then steepens over 30 m (rope necessary), a 12 m vertical followed by a new scree slope closed by a vertical barrier of blocks that prevents connection with the other part of the fault. Depth reached there: approximately 40 m.

Descent from above: approximately 70 m after the start of the fault in the North, a 55 m vertical between the two walls. Approximately 50 m further south, just before the point where the fault bends to the left and the cliff, directly above an enormous block wedged between the walls at -17: a 70 m vertical.

Descent via the South end: one enters through a 2 m step, the stony floor first descends on a fairly gentle slope. After 20 m, at the level of a block barrier, on the right, one can ascend an adjacent fault for about a dozen metres. After climbing the blocks, the main fault is 2 to 3 m wide, the scree floor becomes increasingly steep and requires caution. After about twenty metres, one reaches the top of a 6 m vertical (spit on the left wall 5 to 6 m before for the start of a handline). At the bottom of the vertical, the slope continues very steeply for 10 m, then a 2 m step and one is then at the lowest point (-34 relative to the South entrance, -70 relative to the top of the walls). From there, the floor of the fault rises on a very steep slope for about fifty metres; towards the end, the floor is formed of blocks, and one finally comes up against the wall of blocks that also stops progression when descending via the North end.

At the lowest point, the sky has long since ceased to be visible and the floor is cluttered with plant debris (dead leaves, branches, trunks).