What is the most important factor in mass wasting?

The most important factor in mass wasting is gravity. Mass wasting refers to the downward movement of soil and rock material due to the influence of gravity, which acts to pull these materials down slope. While water can significantly influence the process by adding weight, reducing cohesion among particles, and increasing pore water pressure, it is gravity that ultimately drives the movement. Gravity acts continuously on all materials on the Earth’s surface, creating the conditions necessary for mass wasting to occur.

In the context of mass wasting, when gravitational forces exceed the resistance of the material (rock, soil, etc.), failure happens, leading to a landslide, slump, or other forms of mass movement. Water, temperature, and wind can all play auxiliary roles, modifying the effects of gravity or influencing the stability of slopes, but the fundamental driving force remains gravity itself.