| Term: | Snow |
| Definition: |
Frozen precipitation in the form of white or translucent ice crystals in complex branched hexagonal form. It most often falls from stratiform clouds, but can fall as snow showers from cumuliform ones. At temperatures than -5 CanadaNCA
(1) an ice particle formed by sublimation of vapor in the atmosphere (2) a collection of loosely bonded ice crystals deposited from the atmosphere; high density snow (greater than 550 kilograms per cubic meter; 34 pounds per cubic foot) is called firn if it is older than one year. NSIDCCryosphere (1) Solid precipitation in the form of ice crystals, chiefly in complex branched hexagonal form and often agglomerated into snowflakes; or an accumulation of the same on the Earth's surface. (2) Solid precipitation that has accumulated on the summer surface on a glacier and that transforms to firn at the end of the mass-balance year. See zone. In this sense, which prevails almost universally in the study of mass balance, snow may contain ice in the form of lenses or pipes which are the result of refreezing of meltwater. (3) An accumulation of solid precipitation on a glacier that has not yet attained a density through compaction sufficient to restrict the circulation of air and water significantly. In this structural sense, the dividing line between snow and firn is diffuse but is conventionally taken to be near to a density of 400 kg m-3. IHPGlacierMassBalance Precipitation in the form of ice crystals, mainly of intricately branched, hexagonal form and often agglomerated into snowflakes, formed directly from the freezing [deposition] of the water vapor in the air. NOAA-NWS Precipitation in the form of small ice crystals which may fall singly or in flakes. Deposited snow is a highly porous material that builds up the snow cover on the ground. IACSSnow Precipitation of ice crystals, isolated or as part of a cluster, falling from a cloud. ECCCanada Precipitation of ice crystals, isolated or agglomerated, falling from a cloud. WMOMeteoterm Precipitation of ice crystals, most of which are branched (sometimes star shaped). AustraliaBoM (1) Atmospheric precipitation of ice crystals. (2) Loose and porous aggregation of ice crystals or their fragments on any surface. WMOHydrology Ice crystals precipitated from the atmosphere, mainly in complex hexagon (plate, column or needle) form, often agglomerated into snowflakes IPAPermafrost Ice crystals precipitated from the atmosphere, mainly in complex hexagon (plate, column or needle) form, often agglomerated into Snowflakes. TrombottoGeocryology Precipitation composed of white or translucent ice crystals, chiefly in complex branch hexagonal form and often agglomerated into snowflakes. For weather-observing purposes, the intensity of snow is characterized as 1) light when the visibility is 1 km (5/8 statute mile) or more; 2) moderate when the visibility is less than 1 km (5/8 statute mile) but not more than 1/2 km (5/16 statute mile); and 3) heavy when the visibility is less than 1/2 km (5/16 statute mile). AMSglossary A type of solid precipitation that forms in clouds with an air temperature below freezing. Snow forms when water vapor deposits directly as a solid on a deposition nuclei. Snowflakes begin their life as very tiny crystals developing on a six-sided hexagonal deposition nuclei. The developing snowflak, then grows fastest at the six points of the nuclei as these surfaces are more exposed to atmosphere's water vapor. Snowfall is most common with the frontal lifting associated with mid-latitude cyclones during fall, winter, and spring months when air temperatures are below freezing. PhysicalGeography Precipitation of ice crystals, most of which are branched (sometimes star-shaped). The branched crystals are sometimes mixed with unbranched crystals. At temperatures higher than about -5 C the crystals are generally agglomerated into snowflakes. SPRI GCW |