article_snippet: Cold-loving, fresh-water algae known as Chlamydomonas nivalis that contain a bright red pigment can cause snow to appear red .
article_snippet: But, as reported by JSTOR, when snow is deep enough it can actually appear blue. 
article_snippet: The reason for this is due to ice crystals in the snow, according to the National Snow and Ice Data Centre (NSIDC)
article_snippet: As light waves travel into the snow or ice, the ice grains scatter a large amount of light,’ the NSIDC explains.
article_snippet: When you see just the surface of a pack of snow, the scattering of the light is almost completely impossible to notice.
article_snippet: But if you look into a significant amount of snow, about 3.3ft (one metre) or so, more photons emerge towards the blue end of the spectrum than the red end.
article_snippet: When snow appears red, though, it is for an entirely different reason. 
article_snippet: This effect is due to cold-loving, fresh-water algae known as Chlamydomonas nivalis that contain a bright red pigment.
article_snippet: Also known as ‘watermelon snow’, it is ‘most common during the summertime in high alpine areas as well as along coastal polar regions’.