Snow, the white stuff, without it there'd be no white christmas, or white blanket, but why do a few clear (translucent) ice crystals bunched together look white at all?
We all know the basics of visual color perception; light frequencies travel around and run into things causing them to be absorbed, scattered, or pass right through. The outcome: the frequencies left over make it back to our eye and are interpreted by the brain which reveals before our eyes those beautiful colors we all love so much. Amazing.
So, why is snow white? When white sun light hits snow there are so many pockets of air and ice crystals that it causes a diffuse reflection of the whole spectrum scattering every wave length right back at us, and the combination of all color frequencies appears white.
A glacier is a mass accumulation of snow and ice. However, unlike snow, a glacier's color appears a deep, almost deep-sea-eerie blue. This is because, while white snow sits atop these massive giants, all the previous year's snow has been compressed into ice, and light acts differently in ice. When white sunlight hits a glacier, instead of being completely scattered, like with snow, it penetrates deep into the ice. The farther it goes the more red frequencies get absorbed due to an "overtone of infrared OH stretching mode of the water molecule." This is the same reason water appears blue.
While yellow may be the most colorful snow we in the urban world may've come across, snow colors of green, oranges and reds do naturally exist. One being Watermelon Snow, which is reddish or pink in color, with the slight scent of a fresh watermelon. This type of snow is common during the summer in alpine and coastal polar regions worldwide, such as the Sierra Nevada of California. Watermelon Snow gets its color mainly from Chlamydomonas nivalis, a species of green algae containing a secondary red carotenoid pigment (astaxanthin) in addition to chlorophyll.
As little as 2cm of snow can change the acoustic properties of a landscape. Newly fallen snow acts as a sound-absorbing material due to the trapped air between the individual flakes which trap and dampen vibrations. Because of snow's unique properties the permeability and depth of snow in an area can be measured using a loud sound such as a pistol. If the temperature of snow drops below −10 °C (14.0 °F) snow will squeak when walked upon.
Header image by CaptPiper.
Color Inspiration: Wintery Whites