There are many variances as to how land can slide:

There are landslides where the soil structure is weakened by the rains and ultimately collapses by the sheer gravity of the material (soils and rock), and is called mass wasting. It can happen at a time even when there is no rainfall though it is often induced by an expansion and contraction resulting from the wetting and drying over time. This can be of any magnitude given the nature of the material and how steep the area is; examples are often seen along natural cliffs, in used or abandoned quarries and riverbanks where parts of the banks subside and fall into the river.

In deforested sloping lands, common in the intensive corn lands, there are landslides due to heavy rains that often leave a "giant paw" mark in the landscape where the soil slips from a steeper area and "slumps" into a position just below. Such areas often measure 20 by 10 meters and are not liquid enough to flow to the bottom of the hill.

There are the deep soils that are torn out from under full cover forest during major rainfall events, with all the rock and weathered material loosened below. This occurs due to saturation of the soil, the weight of which cannot be held in place by the vegetation and liquefies usually flowing all the way down to the river at the base.

Such landslides also occur but more frequently on logged-over slopes though the depth of soil loss may not be so great due to a longer history of soil erosion.

Major storms affect mountain streams, loosening up not only all the sediments and bed load, but also the deeper bedrock that was weakened and worn down by water action over longer time periods. During a major event a great volume of this river bed material in a catchment system can be exported onto alluvial fans, flood plains and deltas.

These last three sources of material are partially determined by the underlying rock type, creating a different pattern in the landscape and resulting in different landslide and material redistribution.

Impacts of landslides:

• Immediate loss of lives
• Destruction of infrastructure and property
• Temporary damming resulting in surging flood waters
• Supply of debris and moving riverbed material
• Extending alluvial fans, silting-up of water courses
• Subsequent flooding due to minor rainfall events results from the filling up river beds and delta change toward the end of a major flood event.
• Degradation of the landscape, which may take a decade and more to recover.