Why does everything get so quiet after a snow fall?

There’s nothing like walking around after a fresh snow fall. Everything is so quiet! Ever wonder why that is? Is it simply because everyone is hiding out at home and all the animals are hibernating… or could there be another reason? Turns out, all this quiet after a snow fall can be explained by the nature of sound and how it travels.

Freshly Fallen Snow Absorbs Sound

Sound waves bounce right off surfaces that are hard, smooth, and dense — like concrete or asphalt. As you surely know from experience, freshly fallen snow is neither hard, smooth nor dense. The layers of snow that fall to the ground trap a lot of air between all those snowflakes, and the snowflakes themselves trap a lot of air between their lacy crystalline structures. All this trapped air is what gives snow that velvety and sponge-like texture, and this is why sound waves get absorbed… because they get trapped in all these miniature air pockets. Trapped by the snow, the sound waves can't bounce and make their way into our ears. Snow works a lot like the sound proofing panels you find on the walls of sound studios.

Only Fresh Snow!

After snow has fallen, it will eventually get compacted, hardened, or melt which means it loses its velvety and spongy quality and loses its ability to absorb sound. This is why that snowy silence doesn’t last. Snow that has turned into ice can even cause us to perceive sound as being louder because its surface is smooth and hard and allows sound waves to bounce right off.

Does Cold Weather Also Play a Part?

You bet. Since sound waves travel through the air, air temperature has a part to play too. The way sound waves travel is also influenced by things like air pressure and other atmospheric conditions, but as a general rule, colder temperature increase air density which makes it harder for sound waves to travel. That means it takes more time for sound to reach our eardrums. So when the temperature drops, it can make everything sound quieter since sound waves are generally travelling more slowly… especially in the presence of big fluffy layers of freshly fallen snow trapping all those slow-moving sound waves.

Take the time to head outside after the next snow fall… and enjoy the sounds of silence!

Sources:

Michigan State University : https://www.canr.msu.edu/news/snow_science_silent_snow

University of Kentucky : http://uknow.uky.edu/campus-news/science-behind-snows-serenity

Iowa State University : https://www.nde-ed.org/Physics/Sound/modepropagation.xhtml