|Avalanche path||A terrain feature in which an avalanche occurs, this is normally split into the start zone, track and runout zone|
|Avalanche terrain||Any terrain which has the potential to form or be part of a snow avalanche|
|Bonding||Refers to a snowpack which has undergone some metamorphism and has many links between the individual snow grains, generally leading to a stronger “bonded” snowpack|
|Cornice||An overhanging mass of wind sculpted snow projecting beyond the crest of a ridge|
|Crust||A hard surface layer which can be formed by solar radiation, wind or rain which has the potential to cause instability when buried|
|Destructive Scale of Avalanches||D1: Relatively harmless to people. Typical mass: less than 10 tons.
D2: Could bury, injure or kill a person. Typical mass: 100 tons.
D3: Could bury and destroy a car or truck, destroy a wood frame house, or break a few trees. Typical mass: 1000 tons.
D4: Could destroy a railway car, several buildings, or a substantial amount of forest. Typical mass: 10,000 tons.
D5: Could gouge the landscape; the largest known avalanches. Typical mass: 100,000 tons.
|Freezing level||The elevation at which the air temperature is at 32° Fahrenheit or 0° Celsius|
|Half (1/2)||Used with compass directions, e.g. “lee to the easterly half” refers to the aspects facing west from north through to south|
|Instability||A weakness or lack of stability indicating that additional loads will result in a given probability of avalanche occurrence|
|Lee (leeward)||The side of a mountain protected from the wind (where snow is deposited by the wind and loading occurs)|
|Loose snow||A type of avalanche which originates at a point and spreads out as it descends (aka “sluff” or point release)|
|Melt-freeze||A metamorphic process when snow changes from a solid to a liquid and back again and may result in the formation of a crust.|
|Pockets||Small isolated terrain features|
|Quarter (1/4)||Used with compass directions, e.g. “lee to the easterly quarter” refers to the aspects facing northwest through to southwest|
|Runout zone||The area at the bottom of an avalanche path where an avalanche starts to decelerate and comes to rest; this is where the debris is located after an avalanche has occurred|
|Safe travel technique||The use of appropriate terrain to move given the posted danger scale (e.g. stick to ridges and well away from runout zones, or slopes less than 30°)|
|Shady aspect||The side of a mountain protected from the sun|
|Slab||A cohesive layer of snow|
|Sliding hazard||A hazard posed by very hard or icy conditions, also known as “slide-for-life conditions”|
|Solar aspect||The side of a mountain exposed to the sun|
|Start zone||The area at the top of an avalanche path in which unstable snow may fail; most commonly has an angle greater than 25°|
|Terrain traps||Terrain features which in the event of an avalanche could compound the danger (e.g. gullies, depressions)|
|Track||The area which connects the start zone and runout zone, which can be either confined or unconfined|
|Unsupported slope||Slopes which are not supported by the terrain (e.g convex rollovers)|
|Weak layer||A layer in the snowpack identified as a possible failure plane|
|Wet snow||Snow with a water content greater than 3% and temperature of 32° fahrenheit or 0° Celsius|
|Whumphing||The sounds associated with rapid settlement or collapse of the snowpack, when weighted|
|Wind loading||The transport of snow by the wind causing additional build up of snow on lee terrain or in deposition areas|
|Wind slab||A cohesive layer of snow caused by wind loading|
|Windward||The side of a mountain exposed to wind (from which snow is transported to lee aspects or deposition areas)|