The very rapid downslope flowage of rock fragments, during which the fragments may become further broken or pulverized. Rock avalanches typically result from large rockfalls and rockslides, and their patterns of displacement have led to the term rock-fragment flow (Varnes, 1958). Characteristic features include chaotic distribution of large blocks, flow morphology and internal structure, relative thinness in comparison to large areal extent, high porosity, angularity of fragments, and lobate form. Cf: debris flow. (Neuendorf, K.K.E. and others, 2011)