What is Snow?
[[File:Tree covered with snow.jpg|thumb|right|300px|[[Tree]]s covered with snow]] [[File:Countries_receiving_snowfall.svg|thumb|300px|Occurrence of snowfall: {{Legend|#54E4E4|Snow below 500 meters [[above sea level]] every year.}} {{Legend|#63ABFC|Snow below 500m over sea level, but not in all of its territory (esp. in some coastal and/or desert areas).}} {{Legend|#0000FF|Snow above 500 meters above sea level every year, however it can snow below this level every few years.}} {{Legend|#EC74E4|Snow only above 500 meters above sea level.}} {{Legend|#D300CA|Snow only above 2,000 meters above sea level.}} {{Legend|#C0C0C0|Without snow.}}]] '''Snow''' is a form of [[ice]].<ref>{{cite web |url= http://water.usgs.gov/wsc/glossary.html#S |title=Science in Your Watershed - General Introduction and Hydrologic Definitions |work=water.usgs.gov |year=2011 |accessdate=13 February 2011}}</ref> Snow forms when [[water]] in the [[atmosphere]] becomes [[freeze|frozen]]. It comprises individual [[ice]] crystals that grow while suspended in the [[Atmosphere of Earth|atmosphere]]—usually within [[Cloud|clouds]]—and then fall, accumulating on the ground where they undergo further changes. Snow comes in all different shapes and sizes. At the [[freezing point]] of water (0° [[Celsius]], 32° [[Fahrenheit]]), snow melts and becomes liquid [[water]]. Sometimes, the snow will melt very fast and become [[water vapor]]. This is called [[Sublimation (phase transition)|sublimation]]. The opposite, where water vapor becomes snow, is called [[Deposition (phase transition)|deposition]]. Snow is used for some winter [[sport]] activities like [[skiing]] and sledding. Sometimes people make artificial snow so they can ski. People also commonly build things out of snow for fun. Snow can also be dangerous, as it can lower [[visibility]] and make driving very difficult. When it snows, the snow will melt a little during the daytime and freeze again at night. This makes [[ice]] which can make driving conditions very treacherous. Snow plows are used to