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:
“Like an army defeated
The snow hath retreated,”
—William Wordsworth (1770–1850)
“Physical force has no value, where there is nothing else. Snow in snow-banks, fire in volcanoes and solfataras is cheap. The luxury of ice is in tropical countries, and midsummer days. The luxury of fire is, to have a little on our hearth; and of electricity, not the volleys of the charged cloud, but the manageable stream on the battery-wires. So of spirit, or energy; the rests or remains of it in the civil and moral man, are worth all the cannibals in the Pacific.”
—Ralph Waldo Emerson (1803–1882)
“Nature has no mercy at all. Nature says, “I’m going to snow. If you have on a bikini and no snowshoes, that’s tough. I am going to snow anyway.””
—Maya Angelou (b. 1928)