The transfer of material down hill-slopes. It is the result of gravity acting on material that has lost cohesion, typically as a result of an increase in water content. It includes four main categories: flow, slide, fall, and creep, of which creep is the most important if least spectacular. An avalanche is a rapid and often destructive flow of rock or snow. A slide (or landslide) is a comparatively rapid displacement of material over one or more failure surfaces which may be curved or planar. Failure on an arcuate surface is typical of clays, and gives rise to rotational slides such as those of Folkestone Warren, England.
Subjects: Earth Sciences and Geography — Ecology and Conservation.