skred

Skred is a geological term for a range of mass-wasting events in which rock, soil, or other material moves downslope under gravity. It encompasses phenomena such as rockfalls, rockslides, debris slides, debris flows, and mudflows, as well as snow-related avalanches in some languages. Skred can occur rapidly with little to no warning or progress more slowly as creeping earthflows. Triggers include heavy rainfall, rapid snowmelt, thawing permafrost, earthquakes, volcanic activity, and, in some cases, human activities that destabilize slopes.

Different forms vary in motion, material, and speed. A rockfall involves individual rocks detaching and dropping or bouncing down a cliff. A rockslide involves a coherent mass moving along a discrete plane. Debris slides and debris flows involve mixtures of soil, rock, and water, with debris flows behaving more like fast-moving slurries. Slumps display rotational movement along a curved surface, while earthflows are slower, viscous movements of fine material. Snow-related skred, often referred to as snøskred or snow avalanche in languages dealing with snow terrain, is a related phenomenon in snow-covered areas and is sometimes included under the broader concept of skred.

Impacts and management: Skred can threaten lives, infrastructure, roads, railways, and utilities, especially in mountainous regions and along steep coastal slopes. Monitoring and mitigation include hazard mapping, slope stabilization (drainage control, retaining structures, rock bolts), debris clearing, rockfall nets, and early-warning systems based on rainfall data, ground movement sensors, and remote sensing. Land-use planning and public awareness reduce risk by restricting development in high-hazard zones and maintaining vegetation that helps stabilize slopes.