For anyone wanting uptodate info on the snow situation, the link to the MSC backcountry bulliten is here.
www.avalanche.net.nzand as an aid to interpreting the bulletin below are a few terms and commonly used names.
Glossary of commonly used terms in the NZMSC Backcountry Avalanche Advisories (
www.avalanche.net.nz)
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. (or a weakening, depening on teh situation. ed. hc)
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. ( or simple rise in air temperature
amd then a cooling of teh surface layer. Ed. HC)
Freezing level
The elevation at which the air temperature is at 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
Loose snow (avalanche)
A type of avalanche which originates at a point and spreads out as it descends.
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. stay 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 degrees.
Terrain traps
Terrain features which in the event of an avalanche would compound the effect (e.g. gullies, small bowls)
Track or Path
The area which connects the start zone and runout zone, this can be either confined or unconfined.
Unsupported slope
Slopes which are not being supported by the terrain, e.g convex rolls
Weak layer
A layer in the snowpack identified as a possible failure plane.
Wet snow
Snow with a water content greater than 3% and has a temperature of 0° Celsius
Whumphing
The sounds associated with the rapid settlement or collapse of a snowpack, when weighted.
Wind loading (sometimes reffered to a crossloading depending on terrain shape)
The transport of snow by the wind causing an additional build up of snow on a lee slope
Wind slab
A cohesive layer of snow caused by wind loading
Windward
The side of a mountain exposed to a wind
(and an additional one that Ive added.
Pillow A confined small deeper area of wind blown snow that has collected in the lee of a ridge or terrain feature. ED.HC )