downslope

Downslope refers to the direction or movement toward lower elevations along a slope. It is the direction of steepest descent relative to the terrain and is determined by the slope’s gradient and orientation with respect to gravity. The term is used in geology, hydrology, meteorology, and engineering to describe the path along which material, water, or air tends to move due to gravity.

In geomorphology, downslope is the principal direction of potential movement of soil and rock. Slope stability analyses consider forces acting downslope; mass-wasting processes such as creep, slides, flows, and falls generally occur in the downslope direction, depending on material properties, moisture, and slope angle. The downslope path often concentrates flow into channels or avalanches.

Water and sediment commonly move downslope on hillslopes, initiating surface runoff and channel formation. The downslope flow path is influenced by surface roughness, vegetation, and infiltration. In urban hydrology, downslope routing models predict discharge to streams.

In meteorology, downslope winds occur when air descends a mountain slope, often warming adiabatically. In geographic information science, the downslope direction is computed from digital elevation models to model drainage and flow routing using algorithms that assign a single downslope direction to each cell.