Landslides are another hazard that result from mass wasting. The technical term for landslide is sediment flow, which better describes the fluid nature of its composition and movement. Most sediment flows are a mixture of rock debris, water, and air that flow downhill. Sometimes the movement is a scarcely noticeable centimeter per year. Other times, a volatile mixture of heavy rains and loose sediments creates high velocity mudslides reaching up to eighty kilometers per hour. A tropical storm in 1985 caused a mudslide that buried over 100 homes in Puerto Rico.