Why Is It So Quiet After It Snows?
Have you ever noticed how much quieter everything gets after a significant snowfall?
Howling winds and pouring rain are closely associated with the sound of tornadoes and thunderstorms.
But when it comes to a fresh blanket of snow, there’s largely silence. And it's not just because there are fewer people outside.
David Herrin, associate professor of mechanical engineering at the University of Kentucky, said there’s a simple scientific reason.
“Snow is actually a pretty good sound absorber,” he said.
The characteristics and age of snow can affect how sound waves travel, dampening them in some cases or enhancing them in others, according to the National Snow and Ice Data Center. When the ground has a thick layer of fresh, fluffy snow, sound waves are readily absorbed at the snow surface, dampening sound, according to the center.
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Herrin said snow's ability to absorb sound is comparable to many of the foams and fibers used inside cars and buildings to reduce noise.
Sound absorption is measured on a scale of 0 to 1, with 1 being completely sound-absorbing and 0 being like a concrete floor. Snow ranks closer to a 1 than a 0.
“If we take a look at the sound absorption of snow at the typical audible range, I would say that the sound absorption is on average about a 0.6 or so, which is pretty high,” Herrin said.
Of course, all that can change if snow melts and refreezes, according to NSIDC. If snow becomes smooth and hard, then the surface will help reflect sound waves, which may make sounds seem clearer and travel farther.
But — to state the obvious — actually walking on snow has its own distinctive sound. The sudden squashing of tiny ice grains compresses snow. And the lower the temperature, the greater the friction — and the louder the crunch.
“You’re going to hear the impact of your boot against the snow," Herrin said. "And also, you will hear the ice crunch or snow crunch as it gets compacted."