Snow.

Snow has an artistic, magical quality about it. A landscape draped in a thick blanket of snow can be a magnificent site, and in our towns and cities a thick carpet of snow can, for a short while at least, smooth over the edges of an otherwise harsh environment. Snow is a common and permanent feature of many mountain tops, including Mount Kilimanjaro, in Tanzania, despite being only 3 degrees south of the equator.

Snow is not frozen rain. Snowflakes are created within the clouds by minute crystals of ice repeatedly colliding and sticking together. Snow typically forms at a temperature well below freezing point (roughly -10 C or -14 F), where ice crystals form at the expense of supercooled water droplets (known as the Bergeron-Findeisn process). The end result of all this is snowflakes! The majority of snowflakes will melt on their way to the ground and fall as rain. However when the air temperature near the ground is cold enough snowflakes will fall as snow!

In reality snow will generally reach the ground if the surface temperature is 2 C, and sleet (partially melted snow and rain) is likely at 3 C.

It is untrue that it can be “too cold” for snow, although the heaviest snowfall tends to occur when the temperature is around zero since the air holds more moisture than it does at much colder temperatures.

Every snow crystal is 6-sided (hexagonal) and no two snow crystals are identical (However, with billions of snowflakes falling every year, this is difficult to prove, but accepted as fact).

Some snowflakes can be as large as 5-7 cm (2-3 in) across. Some of the largest snowflakes ever recorded fell over England in April 1951 and measured 12.5 cm (5 in) across.

The speed at which snow falls can vary enormously, but as a rough rule of thumb snow falls at approximately 2 m/s (6 feet/s), which is about a quarter the speed of rain.

If the air temperature is very cold, "dry" snow falls. With dry snow the ice crystals are unable to stick together easily and the snow will be fine and powdery. If the temperatures are near freezing point, "wet" snow falls and much larger snowflakes form, especially if there is no wind.

In very cold dry conditions ‘diamond dust' ice crystals may fall.