steepen

Steepen is a verb meaning to become or to make steeper, i.e., to increase the angle or rate of slope of a surface or landform. The word is formed from the adjective steep with the suffix -en, and is used both transitively (to steepen a slope) and intransitively (the slope steepens with time).

In geomorphology and hydrology, steepening occurs when processes remove material from the base of a slope or add material on top more than it is transported away, causing the slope to incline more sharply. Common mechanisms include undercutting by water, landslides, tectonic uplift, and river incision; vegetation loss and anthropogenic activities such as excavation or road construction can also steepen slopes. Steepening affects slope stability and flood risk; steeper banks are more prone to erosion and mass wasting.

Measuring steepness is typically done by slope angle (degrees) or slope gradient (rise over run). The term steepen describes an observed change (the slope steepens) or a process that causes such a change (erosion steepens a bank).

In other domains, the term is used metaphorically, for example to describe a learning curve that becomes steeper over time or to describe changes in ascent profiles of roads and ski runs.

See also: steep, slope, gradient, landslide, slope stability.