What is the difference between rockslides and rock avalanche?

The difference is in both the source of the slide and the material it is composed of. ROCKSLIDES occur when rock fractures and falls away from exposed rock faces, in a process known in Yosemite as exfoliation, caused by the effects of weathering over time, usually from water and ice seeping down through the cracks in the rocks and freezing/expanding in the winter time. A ROCK AVALANCHE occurs when the aculated silts and soils holding an aggregated field of boulders or previously fallen, yet aculated rubble from rockslides lets go, often from washing away after rainfalls. Rockslides can cause rock avalanches, but not the other way around, see?