The Grand Tetons are fault-block mountains with no foothills, their sharp peaks carved by extensive glacial erosion.
02/02/2026
The jagged peaks and deep canyons of the Tetons were largely sculpted by immense glaciers during the last ice ages. These glaciers carved cirques, U-shaped valleys, and sharp ridges called aretes into the hard crystalline rock.
02/01/2026
A striking feature of the Tetons is their lack of foothills. The Teton Fault runs directly along the base, causing the mountains to abruptly rise from the flat valley floor, creating a sharp geological boundary.