@dillyd Just as with the snow, if the light passes through enough material, the red light is attenuated just enough to give you that beautiful blue colour. It's a gorgeous effect and when I go skiing I always look for it if the snow is deep enough to plunge a ski pole into it - and lo! the blue is there. No one else notices it. It's mine. Just like those sundogs that few others ever see. #Strangeice