While it may not be high on the list of people's favorite weather events, snow is a fascinating phenomenon. Yes, it can make for treacherous travel, but think of the snow day! There are many scientific facts about snow that may make you look at the next storm differently.
Why Does it Snow?
Snow can only form when the temperature in the atmosphere is at or below freezing and there is a certain amount of moisture in the air. Snow crystals form in a moisture-filled cloud and bounce around until they attach to a particle of dust, sand, or something solid in that cloud. Like rain, when snow crystals become too heavy, they fall from the clouds.
When Does Snow Accumulate?
For snow to accumulate or stick to the ground, the ground must be 41 degrees or colder. Wet snow happens when the ground is too warm, which usually occurs in early winter. When snow accumulates under the right conditions, it traps air inside. A fresh snowfall is 90-95% air but will compress as more snow falls on top. When you walk on the snow and hear the familiar "crunch" noise, you are hearing the air "pop" as ice crystals rub against each other (National Snow & Ice Data Center).
Why Are Snowflakes Shaped Differently?
As snowflakes fall through the atmosphere, they change their structure or shape many times depending on the temperature. A snowflake can start shaped like one crystal, melt slightly, and refreeze into a new shape, combine with other snow crystals or go through another temperature change and so on.
Why Is Snow White?
Snow gives off the white appearance because it reflects almost all visible light. Most natural materials absorb some light which gives them a color, but not snow!
It Can Be Too Cold To Snow?!
It's "too cold to snow" when there is not enough moisture in the air because cold air is denser than warm air and holds less moisture--as a form of precipitation, no moisture means no snow.
What Is Thunder Snow?
Thunder is generated when turbulent air masses of different pressures collide, which can happen when atmospheric temperatures are cold enough for snow. Under these rare conditions, we get thunder snow!
Snow is one of the many fascinating events of our natural world that can give us the time to enjoy it for what it is - a day to slow down and enjoy the snowfall!
- Chris Hendershot, Land Steward