Snow

Snow does not start out as what we see fall from the sky. In fact, it is in fact precipitation of ice in a flake or cluster form. The term snow is often used for both the white materials falling out of the sky and that on the ground. However these two forms are completely different. When falling from the sky, it is in the form of crystalline ice. Ice crystallizes in six-sided objects. This can be seen under magnification. After reaching the ground, snow loses it's crystalline shape and becomes granular. Therefore, falling snow and snow on the ground should be considered two different objects because of how they differ. Snow, however, is a great insulator, it protects the vegetation from the cold, even in subarctic temperatures. The downfall however is that large accumulations of snow often cause problems with transportation.

Snow crystals are crystals of ice formed within the atmosphere at temperatures below freezing. This forms due to condensation of water vapor on a very small ice crystal or dust particle. This condensation does not hit a liquid state, it goes directly fr om water vapor to ice. This is known as sublimation. Water droplets can exist at temperatures as low as -40 degrees Fahrenheit. When these droplets come in contact with tiny ice crystals, they began evaporating and freeze onto the crystals nuclei. The formation of these hexagonal structures of ice takes place in uniformity. If an excess of moisture is present in the atmosphere, the crystals change into snow crystals. Typical Snow crystals are see through like glass and are typically from .02 to .5 i nches in diameter. They can be examined best if gathered by a black cloth when the air temperature is at or below freezing.

In the more northern countries, the snow tends to fall as separate individuals pieces, however in warmer parts of the world that still get snow, the individual pieces tend to stick together. This group that these pieces make up is what we call a snowflak e. These snowflakes are sometimes quite large and can reach about one inch in diameter. These large snowflakes can consist of a few thousand crystals. The look of the flake depends on a few variables. These are: how fast they fall, the temperature, the humidity, and the electrical conditions of that particular time. If the crystals spin around a vertical axes as they fall, they will be hexagonal shape d (six sides) and will be almost perfectly symmetric. Snowflakes due to some of these other variables may also be in the form of needles or columns, or they may have an irregular shape.

Once the snow hits the ground or the other snow that has already hit the ground, it has cannot keep its shape. The warmth and the pressure cause them to change. The crystal changes it's shape into more of a rounded form even if the temperature remains b elow freezing. When snow falls on the ground, it tends to have different temperatures to it. The snow closer to the ground being warmer and the snow on the top tends to be colder. The ground snow because of this eventually becomes ice granules. The amount of snow that falls is expressed in a few different ways. It may be talked of in terms of its average depth or in terms of the amount of water that would exist if the snow melted. The average depth may vary due to the varying structure of the snowflakes. This is why snow is often measure in the amount of water that will result if it melted. The ratio of fallen snow to water is 10 to 1. That is if ten inches of snow fell, that would be equivalent to one inch of rain.