Rock Falls & Topples
Rock falls and topples generally occur where bedrock is exposed at the surface of a hillslope. Rocks separate from the total surface along cracks and joints, driven by gravity and erosion. What distinguishes a fall from a topple is simply whether the dislodged rock travels exclusively through open air, or if it pivots on an axis at the base of the slope. In a fall, the rock travels in freefall, in a topple, the rock pivots on an axis.