What is "sturzstrom"

A sturzstrom (German word composed of Sturz (fall) and Strom (stream)) is a unique type of landslide consisting of soil and rock which has a great horizontal movement when compared to its initial vertical drop — as much as 20 or 30 times the vertical distance. By contrast a normal landslide will typically travel a horizontal distance that is less than twice the distance that the material has fallen. Sturzstroms have similarities to the flow in glaciers, mudflows, and lava flows. Sturzstroms flow across land fairly easily, and their mobility increases when volume increases. They have been found on other bodies in the Solar System, including the Moon, Mars, Venus, Io, Callisto, Iapetus, and Phobos.