Landslides can be large and dangerous. They commonly start out as a coherent mass but may break up into a flow if a long distance is covered. Another damaging slide was the Vaiont Dam Disaster in the Italian Alps on October 9, 1963. The 875 ft high dam was completed in 1960 and the reservoir took several years to fill. The dam held, but a 100m high wall of water sloshed over the dam and killed about 3000 people downstream.
Debris flows imply a fluidized mass is moving down slope.
Very damaging flows may accompany volcanic eruptions or earthquakes. Slumps are marked by movement of a coherent mass a short distance along a curved surface. Slumps are less dangerous because they generally move slowly, but they can still do damage to human construction. A fine local example is the slump at the intersection of highway 93 and U.S. 6 in Golden. They are now building houses on top of the slump.