Previous to reaching the half-way spring, where the peasant girls offer strawberries to travellers in summer, we crossed two large couloirs filled with the debris of avalanches which had fallen the night before. Between these was a ridge forty or fifty yards wide on which the snow was very deep, the slope of the mountain also adding a component to the fair thickness of the snow. My shoulder grazed the top of the embankment to my right as I crossed the ridge, and once or twice I found myself waist deep in a vertical shaft from which it required a considerable effort to escape. Suddenly we heard a deep sound resembling the dull report of a distant gun, and at the same moment the snow above us broke across, forming a fissure parallel to our line of march. The layer of snow had been in a state of strain, which our crossing brought to a crisis: it gave way, but having thus relieved itself it did not descend. Several times during the ascent the same phenomenon occurred. Once, while engaged upon a very steep slope, one of the men cried out to the leader, "_Arretez!_" Immediately in front of the latter the snow had given way, forming a zigzag fissure across the slope. We all paused, expecting to see an avalanche descend. Tairraz was in front; he struck the snow with his baton to loosen it, but seeing it indisposed to descend he advanced cautiously across it, and was followed by the others. I brought up the rear. The steepness of the mountain side at this place, and the absence of any object to which one might cling, would have rendered a descent with the snow in the last degree perilous, and we all felt more at ease when a safe footing was secured at the further side of the incline.