The chaos at "La Piche"  refers to the devastion left by a  major landslide which started between 1990 and 1994, as shown in the aerial photos above.

Comparing the views, it can be seen that the landslide, which was located at the bottom right of the oval, oblong shape in 1994, has grown significantly in 2006, destroying parts of the forest tracks.

In the photo opposite, dated 2016, we can see a tendency towards stabilisation and even a recolonisation of the vegetation. The geological map has been superimposed on the photo (the landslide is not coloured). The blue areas correspond to grey marl from the Oxfordian period (160 million years ago), the yellow and pink colours to terrain from the Eocene and Oligocene periods(37 to 25 million years ago) composed of white or coloured marl, sandstone and limestone with microfossils (nummulites, globigerines) or plant debris. Levels or layers of conglomerate rocks with mixed pebbles coming from the rocks of the internal Alps (green rocks, radiolarites) complete this very heterogeneous (diverse mix) group of rocks in this landscape, which has been totally disrupted by the landslide.

Landslides are frequent in the region. The creation of additional mountain-tracks along with the possible natural movement of geological fault-lines contribute to the instability of the slopes and triggering landslides.