The Gourfouran ravine

During the major glaciation periods, the enormous Durance glacier carved out its bed to a depth of more than 200 metres. The glacier in the Freissinières valley flowed onto the surface of this glacier. When they melted, they left a large "stair step”, called a confluence terrace. Flowing into the Durance, the Biaysse gradually carved a path through this terrace, first as a subglacial mountain stream and then after the glacier melted.