Term: Snowline Class:  
 vernacular   (0%)
Created 6 June 2017
Last modified 6 June 2017
Contributed by GCW Glossary


Definition: (1) Climatic snowline: lowest altitude of a continuous layer of snow on the high mountains in summer. (2) Orographic snowline: lowest altitude at which snow persists on the land surface as isolated coverings on the mountains in summer.  WMOHydrology 

A set of points forming the lower limit of a snow-covered area; on a glacier, the line separating snow surfaces from ice or firn surfaces, and also separating the percolation zone from either the superimposed ice zone or the ablation zone (see also zone). The set of points need not form a continuous curve. The snow-covered area of the glacier may include outliers (isolated patches of snow surrounded by firn or ice) and may exclude inliers (isolated patches of exposed firn or ice). The snowline is usually easy to see, because the snow above it is brighter than the firn or ice below it. It may therefore be mapped by analysis of suitable imagery. When, and only when, there is no superimposed ice, the snowline coincides with the equilibrium line. Unless qualified by a different adjective, references to the snowline are understood to refer to the Annual snowline. It is common for 'snowline' to be used as an abbreviation of 'average altitude of the snowline'.  IHPGlacierMassBalance 

In general the outer boundary of a snow covered area. This may be the ever-changing latitudinal limit of snow cover, particularly in the Northern Hemisphere winter, or the lower limit in altitude of the permanent snow cover in mountainous terrain. The latter strongly depends on the aspect of slope. Snowline should not be confused with snow level.  IACSSnow 

The lower boundary of a highland region in which snow never melts  IPAPermafrost