It reflects the color of the sky, blue sky, blue shadows. Grey sky, grey shadows. It is dynamic and changes hourly through out the day.This observation is from 12 years skiing & 14 years snowboarding.
Easy snow mix:
Future, Flat white acrylic paint, a few drops of clear blue acrylic paint. Clear 'smoke' can be substituted for grey sky above. Use this as a wash for footprints ect. Thicken with Talc (baby) powder. Dry brush flat white for the top of the snow. Talc powder can be used last for a 'frosty' look. Take model or diorama out doors and mask or cover everything NOT wanted to look frosty. Pour liberal amounts on scene and blow excess off. DO NOT spray flat clears after this as it will be soaked up and ruin the effect.