The formation of snow begins when water vapor condenses into ice crystals within the clouds. The ice crystals freeze and stick together, forming snowflakes. The air temperature must remain below zero degrees Fahrenheit, but near freezing, to form snow. Snow is the most common precipitation type during the winter season.
The density and moisture content of snow vary. Coastal regions tend to have heavier snow than continental ones. Snow can also be light and dry. Skiers and snowboarders prize light, dry powder. Powder snow often falls from fog or stratus. It can also form large piles of snow near vertical surfaces. These large piles of snow are not typically recorded by meteorologists, but they can still be very impressive.
Snow forms when temperature is low and the amount of water vapor in the atmosphere freezes. It can also be produced by hoar frost or falling ice fog particles. Snow is less dense than rain, so the same amount of water will produce a greater volume of snow. In fact, water in eight units of snow is equal to one unit of water in one unit of rain.
The amount and location of snowfall are key factors in determining whether snow will fall. Generally, the higher the latitude, the lower the chance of snowfall.