Mass wasting occurs where slopes are particularly steep , although some type of movement is occurring on practically every slope. A relationship exists between the type of material that is transported and the speed that occurs. For example, rock and regolith is solid and brittle, so that most mass movements either slide, roll, or fall. However, sediment is prone is being saturated with water, causing a more fluid flow. Soil creep is a slow imperceptible movement of soil and regolith downslope caused by wetting and drying, growth of frost needles, heating and cooling, and trampling and burrowing.
Soil creep causes fence posts and utility poles to lean in the downward direction.
Evidence for soil creep can be seen in road cuts that show the upper layer of the soil pointing downslope. An earthflow occurs when a mass of water-saturated soil or regolith moves down a steep slope during a period of a few minutes to a few hours, and can involve many tons of material. It commonly blocks roadways and larger earthflows can cause significant property damage. A slump is a type of earthflow that occurs when the upper layer of soil and regolith rotates in a curved basin, causing a steep scarp on one end and a bulging toe on the other. A special type of earthflow occurs in the higher latitudes where one finds soil that is frozen for most of the year.