Yet very few people know the science behind landslides. This page should hopefully provide some insight into the fear behind El Nino. In scientific terms landslides are referred to as mass movement. If resisting forces exceed the driving forces, the material will stay in place. However, if the driving forces are greater than the resisting ones, the material will break loose and move downslope, a process called mass movement.
Slides move in contact with the underlying surface.
Flows are plastic or liquid movements, in water and more rarely in air, in which the mass breaks up and flows during movement. Rockfall often is initiated when water freezes in rock crevices. As the water freezes, it expands and exerts pressure on the crevice walls, breaking the rick apart, in a process called frost wedging. Rockfall is an extremely rapid process and thus is a serious geohazard. It can demolish structures near the bases of cliffs and is a danger to motorists where a highway cuts through rocks.