Why Does it Snow
Primarily, it needs to be cold out for it to snow, lower than 32°F though all the different layers of the atmosphere. As the atmosphere is layered, if they are all not below the freezing point, we could get just plain rain, hail or sleet.
Let’s first start at the beginning with precipitation which can come in several forms. For us to get rain, water vapor in the atmosphere needs what is commonly referred to in the scientific community as a “condensation nucleus”, which can be tiny particles of either dust or pollen which are swept up high into the atmosphere. When the condensing droplets that form the cloud get large and heavy enough to overcome the upward pressure of what is called convection, they start to fall. If the temperature all the way to the ground is above freezing, then we get rain! When ice crystals form high up in the cloud, and it’s below the freezing point of water all the way down, then we will get snow. But when there are alternating layers of air above and below freezing, you get other types of precipitation.
When snowflakes fall through a region of the cloud where there’s liquid water which coats the flake with more and more layers of new ice, you begin to get hail. When a thunderstorm’s updrafts are strong enough, some of the young hailstones are swept back up and repeat their journey, getting coated with more and more layers of ice. Eventually they grow so big that not even the strongest updraft can keep them aloft, and so they fall to Earth, in sizes from that of a pea to a golf-ball, and up to the record holder–6 inches long and 17 inches in diameter!
Freezing rain occurs when earth and objects on the surface, such as roads, tree limbs and power cables, are at temperatures below 0° Celsius, 32° F. Above the ground, however, falling snow first encounters a layer of somewhat warmer air, which melts the flakes, and then, right above the surface, a very cold layer, which makes the liquid water “super-cooled”, ready to freeze. The primary cause is encountering the freezing surfaces, and the following results lead to a thin, sometimes transparent film of ice.
Fun Facts about Snow
Did you know that snow is made of ice crystals? If you look at one with a magnifying glass you can see the tiny ice crystals of frozen water that are frozen together to make snowflakes. Moisture is obviously needed for this process, and cold temperatures.
Is it ever too cold to snow? It can snow at very low temperatures; just take a look at Antarctica, where temperatures reach many degrees below 0! It is more common though for most heavy snowfalls with relatively warm temperatures near ground level, or 15°F or -9° Celsius or warmer, due to the fact that the atmosphere can hold more water vapor when the temperatures are warmer. Did you also know that no two snowflakes are ever alike? Some of the larger snowflakes can be up to two inches wide! Most snowflakes are less than a half inch though.
Did you know it can snow when ground temperatures are above freezing as long as atmospheric temperatures are below freezing and the air contains the minimum moisture levels.
Did you know that snow is edible? Yes, it edible, however snow in most urban areas contain pollutants that you should avoid, also animal droppings may contaminate snow, so don’t you eat that yellow snow!
We hope we have answered your question why does it snow, and you have a wonderful winter in the winter wonderland. Peace my friends!