After yesterday’s heavy snow fall I went out for a long walk today. One of the most noticeable changes (apart from my camera underexposing every shot because of the whiteness) was the way the acoustic environment had changed.

Everything sounds different, everything is dulled and deadened

Why does snow have such an effect on sound? Snow – at least new fallen snow – is a matrix of ice crystals, with lots of air held within it. It acts like a damper, like a silencer on a car. Once sound waves get inside the matrix they get absorbed, bouncing around within the air spaces. Snow has a high reverberation absorption coefficient, particularly in the high frequencies. It’s even higher than the acoustic wool which is used in the soundproofing of acoustically treated rooms.

Sound is normally bouncing off all the surfaces around us. Walls of buildings, fences and trees, all are reflecting sound back at us. This might be sounds we produce ourselves, voice or footsteps, or sounds produced artificially. The surfaces around us are normally reflective. As soon as we have a layer of snow all that reflection is gone. No more echo, no more reverberation – at least until the snow has been hard-packed.

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