Landslides occur when rock, dirt, and other debris move or fall down a slope. A landslide also may be called a “debris flow” or a “mudslide,” which flows through channels saturated with water. Landslides may be caused by storms, earthquakes, fires, volcanic eruptions, freezing and thawing cycles, erosion, or man-made construction. They can be small, large, slow, or rapid as well as extremely destructive.