I stopped to look at the view and noticed that the post hole in the snow looked quite like it had blue light about 10cm down. I found this explanation http://www.webexhibits.org/causesofcolor/5C.html Some light penetrates the snow surface and travels downwards. It is scattered or absorbed by the ice crystals. Red and yellow are best absorbed. You can find a graph of it here http://www.webexhibits.org/causesofcolor/5B.html The blue is scattered and bounced around. That's what you see.
