Why Do We See Snow As White?
By Bethan
If water is clear, and ice is usually clear, then why is snow white?
Snow is made up snowflakes, which are made up of many small ice crystals, all differing in shape and structure and these ice crystals reflect light equally. As the light is reflected back equally, it includes all the wavelengths of visible light which when reflected together, appear white. This doesn't happen with water or ice as the visible light rays can pass through undisturbed and are not reflected or absorbed so therefore our eyes can't process them (1).
Although, in the Artic, there are large glaciers that look blue, despite being the same ice that we also see as clear. This is because light enters them through crevices and as it travels through the glacier it gets scattered by ice crystals. Professor Kenneth Libbrecht said that ice and water 'preferentially absorb more red light than blue light ' so when the light rays do emerge, the shorter, blue wavelengths reflect towards our eyes, which is why we see glaciers as blue. Unfortunately, this blue colour is only apparent with snow that's at least a few feet in depth according to The National Snow and Ice Data Centre (2).
(2)- https://nsidc.org/cryosphere/snow/science/characteristics.html