Términos de Avalancha
S
- Sastrugi
Wind eroded snow, which often looks rough like frozen waves. Usually found on windward slopes.
- Settlement
The slow, deformation and densification of snow under the influence of gravity. Not to be confused with collasping
- Ski cut
A stability test where a skier, rider or snowmobiler rapidly crosses an avalanche starting zone to see if an avalanche initiates. Slope cuts can be dangerous and should only be performed by experienced people on small avalanche paths or test slopes.
- Skin track
Backcountry skiers and some snowboarders ascend slopes using climbing skins attached to the bottom of their skis.
- Slab
A relatively cohesive snowpack layer.
- Snow density
The mass of snow per unit volume, but often expressed as a percent water content. New fallen powder has a low density (3-10%), while heavy or wet snow is more dense (10-20%).
- Snow layer
A snowpack stratum differentiated from others by weather, metamorphism, or other processes.
- Snow Metamorphism
The physical change of snow grains within the snowpack due to differences in temperature and pressure.
- Snowpit
A pit dug vertically into the snowpack where snow layering is observed and stability tests may be performed. Also called a snow profile.
- Soft slab avalanche
- Stability
The chance that an avalanche will not occur, relative to a given trigger (usually the weight of a human).
- Stability Test
A procedure used to estimate the stability of the snowpack, often done in a snowpit. Common tests include the Rutschblock, compression or tap test, cornice drop, and slope cut
- Starting Zone
The portion of an avalanche path where an avalanche releases.
- Stepping down
When a slab avalanche slides a short distance and breaks down into deeper weak layers forming a stair-step pattern on the bed surface.
- Sun Crust
A snow layer melted by radiation from the sun and subsequently refrozen.
- Surface Hoar
Featherly crystals that form on the snow surface during clear and calm conditions - essentially frozen dew. Forms a persistent weak layer once buried.
- Sympathetic Trigger
When one avalanche triggers another avalanche some distance away.