White it wasn't. Can't use the paper to portray it. Besides it was at least two tone - one in the sun, one in the cloud shade.
If you look closely at the snow it consists of small mirror like ice particles. That is why it takes on the colour from its surroundings. That is why it can be lighter that the light source of the sky - all those mirror surfaces lining up. Now, if you open your eyes and use a colour isolator (small hole in a mid value gray card) you will see that the snow is comprised of a number of colours. In addition, the edges of snow shadows are even more interesting.