Snow

Snow is a form of precipitation in the form of crystalline water ice, consisting of snowflakes that fall from clouds. Since snow is composed of small ice particles, it is a granular material. It has an open and therefore soft structure, unless packed by external pressure. Snowflakes come in a variety of sizes and shapes. Types which fall in the form of a ball due to melting and refreezing, rather than a flake, are known as graupel, ice pellets or snow grains. Snowfall amount and its related liquid equivalent precipitation amount are determined using a variety of different rain gauges.

The process of precipitating snow is called snowfall. Snowfall tends to form within regions of upward motion of air around a type of low-pressure system known as an extratropical cyclone. Snow can fall poleward of these systems' associated warm fronts and within their comma head precipitation patterns (called such due to the comma-like shape of the cloud and precipitation pattern around the poleward and west sides of extratropical cyclones). Where relatively warm water bodies are present, for example due to water evaporation from lakes, lake-effect snowfall becomes a concern downwind of the warm lakes within the cold cyclonic flow around the backside of extratropical cyclones. Lake-effect snowfall can be locally heavy. Thundersnow is possible within a cyclone's comma head and within lake effect precipitation bands. In mountainous areas, heavy snow is possible where upslope flow is maximized within windward sides of the terrain at elevation, if the atmosphere is cold enough.

Read more about Snow:  Forms, Cause, Snowflakes, Types, Density, Acoustic Properties, Snowfall Measurement, Records, Snow Blindness, Relation To River Flow, Effects On Human Society, Damage, Design of Structures Considering Snow Load, Extraterrestrial Snow

Famous quotes containing the word snow:

    Snow, snow over the whole land
    across all boundaries.
    The candle burned on the table,
    the candle burned.
    Boris Pasternak (1890–1960)

    Rigidly they
    Persisted, linked, through lengths and breadths
    Of time. Snow fell, undated.
    Philip Larkin (1922–1986)

    And before, with banner red,
    Through the blizzard snow unseen,
    All unharmed by hail of lead,
    With a step like snow so light,
    Showered in myriad pearls of snow.
    Crowned in wreath of roses white,
    Christ leads onward as they go.
    Alexander Blok (1880–1921)