SheSue Experience

Lo. sifted through the winds that blow, Down comes the soft and silent snow, White petals from the flowers that grow In the cold atmosphere.
Author: George W. Bungay

What is it about snow that draws us to the windows. No matter how much we hate to drive in it, no matter how much we don’t like it to be cold, no matter how much we long for sunny skies, we all love the snow. We’ve been dealing with the snow for several days here in the Pacific Northwest and the weather prediction says it’ll be around for another week. We all grumble, yet those tiny white flakes always bring a smile. I drive to work on snowy roads, the world white around me. The trees are laced with white, there is a hush all about you and you feel insulated from all the troubles of the world.  I love to see the white flakes against my black coat and I love to hear the crunch under my feet when I step on it.

Here are some facts about snow from a website called All About Snow.

Is it ever too cold to snow?

No, it can snow even at incredibly cold temperatures as long as there is some source of moisture and some way to lift or cool the air. It is true, however, that most heavy snowfalls occur with relatively warm air temperatures near the ground – typically 15°F or warmer since air can hold more water vapor at warmer temperatures.

When is it too warm to snow?  How does snow form if the ground temperature is above freezing?

Snow forms when the atmospheric temperature is at or below freezing (0 Celsius or 32 Fahrenheit) and there is a minimum amount of moisture in the air.

Why is snow a good insulator?

Fresh, undisturbed snow is composed of a high percentage of air trapped among the lattice structure of the accumulated snow crystals. Since the air can barely move, heat transfer is greatly reduced. Fresh, uncompacted snow typically is 90-95 percent trapped air.

Why do weather forecasters seem to have so much trouble forecasting snow?

Snow forecasts are better than they used to be and they continue to improve, but snow forecasting remains one of the more difficult challenges for meteorologists. One reason is that for many of the more intense snows, the heaviest snow amounts fall in surprisingly narrow bands that are on a smaller scale than observing networks and forecast zones. Also, extremely small temperature differences that define the boundary line between rain and snow make night-and-day differences in snow forecasts. This is part of the fun and frustration that makes snow forecasting so interesting.

Does snow change how sound waves travel?

Yes, when the ground has a thick layer of fresh, fluffy snow, sound waves are readily absorbed at the surface of the snow. However, the snow surface can become smooth and hard as it ages or if there have been strong winds. Then the snow surface will actually help reflect sound waves. Sounds may seem clearer and travel farther under these circumstances.

Why does snow crunch when you step on it? At what temperature does it crunch?

A layer of snow is simply composed of ice grains with air in between the ice grains. Because the snow layer is mostly empty air space, when you step on a layer of snow you compress that layer—a little or a lot, depending on how old the snow is. As the snow compresses, the ice grains rub against each other. This creates friction or resistance; the colder the temperature, the greater the friction between the grains of ice. The sudden squashing of the snow at lower temperatures produces the familiar creaking or crunching sound. At warmer temperatures, closer to melting, this friction is reduced to the point where the sliding of the grains against each other produces little or no noise. It’s difficult to say at what temperature the snow starts to crunch, but the colder the snow, the louder the crunch.