How Do Glaciers Shape the Land?
About 19,000 years ago, the Earth was in the midst of a massive Ice Age, during which continental glaciers existed as far south as Wisconsin, most of England and Ireland, southern Germany, and most of present-day Russia. Canada, Norway, Sweden, Finland, and most of Russia were uninhabitable, completely covered in ice. In other parts of the world, such as California, alpine glaciers were much larger and more pervasive, carving numerous features into the mountains which remain today. A glacier forms when snow falls and fails to melt, piling up over the centuries into slabs of ice between a few dozen feet and two miles thick. These glaciers bear tremendous weight, crushing the land beneath them as they slowly flow downhill. They carve out pathways known as glacial valleys. Alpine glaciers coalesce in areas where they can flow downhill easily, creating ribbed patterns between glacial “rivers” (cirques) and “hills” between them (aretes). These glacial features remain thousands or millions o
