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How do rivers and glaciers remove rock from mountain ranges?

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A car drives along the Trans-Canada Highway with Mount Sir Donald's sharp, snow-capped peak rising above forested slopes in the Selkirk Mountains, British Columbia. — mountain Mount Sir Donald in the Selkirk Mountains, British Columbia, looms above a segment of the Trans-Canada Highway.

Rivers and glaciers remove rock from mountain ranges through distinct erosional processes that reshape the landscape over time.

River Erosion

Rivers primarily erode mountains through the scouring action of moving water, which is intensified by the sediment load they carry. As water flows, it entrains particles—ranging from fine silt to large boulders—that act as abrasive tools, grinding against the riverbed and banks to deepen and widen channels. This process is particularly powerful during periods of high flow or flooding. In mountainous regions, tectonic uplift often rejuvenates rivers, increasing their velocity and erosive power, which allows them to carve deep, narrow canyons and gorges through resistant bedrock.12

Glacial Erosion

Glaciers remove rock through two primary mechanisms:
* Abrasion: Glaciers act like massive sheets of sandpaper. Rock debris embedded in the base of the ice grinds against the underlying bedrock, creating features such as scratches, gouges, and polished surfaces.31
* Plucking (Quarrying): Glaciers remove larger blocks of rock by forcing ice into fractures and joints. Through processes like pressure changes and the refreezing of meltwater, the ice pulls these fractured pieces away from the bedrock.31

Unlike rivers, which typically carve narrow V-shaped valleys, glaciers reshape entire valleys into broad, U-shaped profiles and carve sharp peaks, such as horns and arêtes, through extensive erosion of the valley floor and sidewalls.45