The upper limit of the vertically falling rocks on the Unterbächhorn, the Hohstock and the east adjacent ridge to the Sparrhorn refer to the highest traces of glaciation during the last ice age (Würm). At that time the Belalp was covered by a 500 m thick layer of ice. Only the highest peaks stuck out of the ice. The two distinct and with vegetation overgrown moraine ramparts of the Unnerbäch glacier beneath the Hohstockgrat emerged towards the end of the last Ice Age around 12.400 years ago. The debris transported by the glacier were deposited at the edge of the ice during a standstill after an advance phase. Once the glacier retired and the ice melted, the debris remained as moraine ramparts. These tracks help today to reconstruct the outlines and the ice thicknesses of former glaciers.