glacial valley

A glacial valley is distinguished by its distinctive U-shape: a broad flat floor flanked by high walls of rock. Such a valley has been bulldozed wide by a glacier scraping its way down an existing V-shaped valley, created by a preglacial river. Glacial valleys are common in the mountains of the American West and Alaska. In Prince William Sound and southeast Alaska, some of these classic-shaped valleys start deep in coastal mountain ranges and run into the sea later to become water-filled fjords. California’s Yosemite Valley is one of the United States’ most celebrated glacial valleys, and John Muir was the first to explain its icy origins. In his 1912 book The Yosemite, he writes: “These bald, westward-leaning rocks, with their rounded backs and shoulders [facing] the glacier fountains of the summit-mountains, and their split, angular fronts looking in the opposite direction, explain the tremendous grinding force with which the ice-flood passed over them.”

Carolyn Servid