How Glaciers Erode Land

A glacier is a massive, slow-moving river of ice. Glaciers form when snow piles up year after year in cold places and gets packed down into thick ice. These giant ice rivers can be as large as entire cities and move very slowly across the land. Understanding glaciers helps us explain how many of Earth's landforms were created.

As a glacier moves, it acts like a giant piece of sandpaper scraping across the ground. The ice and rocks frozen in the bottom of the glacier erode, or wear away, the land beneath it. Erode means to slowly break down and remove rock and soil. The glacier grinds rock into powder and picks up huge boulders, soil, and everything else in its path. This powerful scraping carved many of the valleys, lakes, and landforms we see today. A valley is a low area of land between hills or mountains, and a lake is a large body of water surrounded by land.

The Great Lakes, located between the United States and Canada, were carved by glaciers thousands of years ago. When a glacier melts, it drops all the material it was carrying. This process is called deposition. Deposition means dropping off or leaving behind sediment and rocks. The melting glacier leaves behind hills made of rock and sediment, which is a mixture of sand, soil, and small pieces of rock.

Interesting Fact: Yosemite Valley in California was carved by glaciers, and some of the rocks the glaciers scraped are as smooth as glass!