Why does it become so quiet after a fresh snowfall?
In the moments after a snowstorm concludes, leaving behind a landscape shrouded in white, the great outdoors often becomes noticeably quieter.
As it turns out, there's a scientific reason behind the calming silence, with the characteristics of snow playing a big role in how sound can travel.
When light, fluffy snow accumulates on the ground, it acts as a sound absorber, dampening sound waves much like commercial sound absorbing products.
“Snow is going to be porous, and typically porous materials such as fibers and foams, and things of that sort, absorb sound pretty well,” said David Herrin, a professor at the University of Kentucky’s College of Engineering who studies acoustics.
Residential street covered in snow with sunny sky. (Photo/LynnKHansen)
Usually it takes a couple of inches of snow, but even an inch can be reasonably absorbing especially if you go higher in frequency, according to Herrin.
Sound absorption is measured on a scale from 0 to 1. Based on previous measurements, sound absorption for snow is in between 0.5 to 0.9, Herrin said.
"That implies that a good amount of sound is going to be absorbed," he said.
However, as the structure of snow changes, the amount of noise in the surrounding environment could increase.
When the snow surface melts and refreezes, it can become hard and reflect sound waves, causing sounds to travel farther and become clearer, according to the National Snow and Ice Data Center (NSIDC).
“Generally after a snowfall, the sound absorption is going to be at a maximum then,” Herrin said. “After a snow has gotten hard or icy, then a lot of the sound is going to bounce back or be reflected at that point.”
“It doesn’t seem as quiet outside in that case.”
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