Water erosion is the most significant type. Rain moves rocks and bits of soil on the land, while the banks of rivers and streams constantly change as water flows through them. Water forms canyons and valleys, and it changes the shape of coastlines. There are several subtypes of water erosion including splash erosion, rill erosion, gully erosion, bank erosion, thermal erosion and coastal erosion.
While not as far-reaching as water erosion, wind causes erosion. In particular, wind carries soil, dust, sand and ash from one place to another, and can gradually change landscapes. Wind and water erosion often occur together. Wind erosion has the greatest impact in parts of the world that are arid.
Ice also erodes the land. This occurs as glaciers move. When they do this, boulders, rock, sand and soil are moved from place to place. Glaciers also scrape and grind the land and rock, changing its shape. During the ice ages, the continents as they are today were formed through erosion caused by ice.