Not so dark
When I say I live in Norway people often react by saying that they couldn't live there because of the dark winters. Well its not dark all winter where I live, about 150km North of Bergen. At the moment we actually see the sun for about 2 hours, and then it drops down behind the mountain but doesn't actually get dark for another couple of hours. The photo was taken about 2 hours after the sun went down, so it doesn't start getting dark until about 4 o'clock, that's about the same as the UK isn't it? some years ago I I visited South Africa to run a workshop, I remember that once the sun went down it got dark almost straight away. Since the sun isn't visible the light reflected of the land must be light scattered by the atmosphere, blue light scatters most so the snow should have a blue tinge. I tried analysing the photo by taking a colour sample in paint.net to see if it did have a lot of blue in it. The results look like they support the theory but I will have to try comparing this with a photo in direct sunlight.