Snow

Snow is one of the two common solid forms of water, the other being ice.

Snow is rain that freezes at -4°C from clouds and forms as it falls from the sky. The temperature required for snow to form is close to 0°C (from about minus 2 to plus 2 degrees). The water thus becomes small star-shaped snowflakes, which are microscopic crystals. Crystallization is the transition from liquid to solid.

In the mountains, one can observe this meteorological phenomenon, called the rain-snow line, which changes with altitude. For example, if the weather forecast announces the limit at 1,500 meters altitude, this means that at 1,400 m it rains because it is slightly warmer, and at 1,600 m it snows because it is slightly colder.

Snow melts as the temperature rises. On horizontal ground, it seeps into the ground and feeds the groundwater tables. On slopes, meltwater collects and forms torrents with a nival regime, or nivo-glacial if it is also fed by meltwater from a glacier.

The process of snow precipitation is called snowfall. A blizzard is a very strong snow storm.

Snowfall usually occurs in regions that are not near the equator or that are at a high elevation, like mountains, especially during the season of winter.

Different aspects of snow[change | change source]

Fresh snow resembling powder is called powder snow
Snow that is half melted is described as slushy
Hardened and frozen snow is called crusted snow

Different types of snow formations[change | change source]

A snowdrift is a pile of snow formed by the accumulation of snow in a confined space, most often under the action of the wind
A firn is a thick layer of hardened snow that lasts from one snow season to the next. It is often the basis for the formation of a glacier.
An avalanche is a mass of snow that breaks away from a mountainside, with devastating effects.