Snowflakes are small ice crystals. Snowflakes near their melting temperature can, through hand pressure, be made to fuse into a snowball by a process of melting and re-freezing. The snow yields to pressure “gently and progressively” and doesn’t make sound. On the other hand, if the snow is very cold, far below its melting temperature, even the pressure of a boot heel or a wagon wheel won’t melt it. The snow is powdery and won’t form snowballs. Instead, pressure just makes the ice crystals crush and slip over each other as dry particles. That “abrupt and jerky” motion of the dry ice crystals causes vibration and sound, according to Humphreys’ book. So W.J. Humphreys claimed that snow creaks when the weather is very cold, but not when the weather is only moderately cold. Does that claim jibe with your experience?