Snow
From Wikinfo
[[sv:Sn�]] For other use, see snow (disambiguation).
Snow, a form of precipitation, is a crystalline form of water ice, consisting of a multitude of snowflakes. Since it is composed of small rough particles, it has an open and therefore soft structure, unless packed by external pressure. It is commonly formed when water vapor sublimates high in the atmosphere and then falls to the ground, although it can be manufactured using snow cannon.
Snow fall varies by time and location, including geographic latitude, elevation and other factors which affect weather in general. In Southern latitudes, there is less chance of snow fall. Some mountains, even at or near the equator, have permanent snow cover on their top.
Many regions of the Arctic and Antarctic receive very little precipitation and therefore little snow.
Substantial snow fall sometimes disrupts infrastructure and services even in regions that are accustomed to them. Traffic may be snarled or even completely stop. Basic infrastructure such as electricity and gap supply can be shut down. A snow day is a day on which school or other services are cancelled owing to massive snow fall.
Forms of recreation depending on snow:
- many winter sports
- playing with a sled
- building a snowman
- throwing snowballs mutually in a snowball fight or to others to tease them.
Where snow is scarce but the temperature is low enough, snow cannons may be used to produce an adequate amount for such sports.
Tightly packed snow may be used as a construction material in, for example, Inuit snow houses.
The concept that no two snowflakes are alike is incorrect: in a volume of snow two feet square by ten inches deep there are roughly one million flakes, and so statistically many snowflakes must be visually identical. The American Meteorological Society has reported that matching snow crystals were discovered by Nancy Knight of the National Center for Atmospheric Research. The crystals were not flakes in the usual sense but rather hollow hexagonal prisms.
See also
External Links
References
- Adapted from the Wikipedia article, "Snow" http://www.wikipedia.org/wiki/Snow September 24, 2003
