Why are glaciers important? They are not just massive flows of ice and snow that scour the landscape and drop dirt and rocks as they melt. They are an important store of water that falls as snow. As the ice and snow melt in the summer, they feed streams that supply water for drinking and irrigation. If water is not stored in glaciers in winter, then rivers and streams supply less or no water in the summer growing season, thus lessening crop yields. Glaciers are essential for the growth of food in many parts of the world.