Canadians like to claim that they can tell the temperature outside by the sound the snow makes underfoot.
The topic has not been well studied, but researchers from the University of Wisconsin suggest that, at temperatures above -10C, the pressure of a foot causes a thin layer of snow to melt, producing a crunching sound as it compresses. Closer to zero, the sliding of grains becomes a squelch as the snow approaches the condition of slush, but as the temperature approaches -10C the snow becomes progressively crunchier.
Below -10C though, the dominant sound is the ice crystals themselves being crushed, producing more of a squeaking. The lower the temperature, the more the ice crystals tend to stick to each other, which creates more friction, so the louder the squeak.
The exact sound also depends on the depth of the snow and the type of surface beneath, and how long the snow has been on the ground. But although there are complex factors at play, it seems plausible that someone who has spent a lifetime trudging through snow really could learn to distinguish the sound associated with different temperatures.
In particular, they might recognise the warning squeak that means it is too cold to be out and they need to turn around and head back inside.
