When your foot comes down on the snow, your body weight exerts additional pressure on the snow crystals underfoot. When it's "warmer" out in winter, the extra pressure actually causes some of the snow to melt underfoot. ... The resulting sound is the squeaking you hear on cold winter days and nights.

Why does snow crunch under your feet?

From the few (sketchy) sources I saw, it looks like the crunch sound comes from the sudden release of air from the air pockets in a pile of snow. ... If the snow is colder, it does not melt, and your boot crushes those innocent ice crystals, accounting for that plaintive scrunching sound.”

What sound does snow make underfoot?

When we walk on new snow, these tiny branches break up by the thousands and that causes the crunching sound we hear." NARRATOR: So snow's crunching sound is down to the delicate ice branches.