The reference photo for this piece was taken in Flagstaff, Az. The pictures I took that day are the only really good ones I have of snow falling and large trees gracing the landscape. It was quite a surprise the day we went through Flagstaff because we traveled from Sedona where it was sunny, cold, and clear to a virtual blizzard. These cities are only about 30 miles apart, but the elevation makes quite a difference.
It is always a bit of a challenge to paint snow scenes and keep them interesting because there is so much "gray". I opted to lean my grays towards the purple side so I used Alizarin Crimson, Ult. Blue, and Cad. Yellow Light to create most of the grays in this landscape. The "grayed down" purple plus a lot of white created a soft lavender which gives a bit of life to the background.
To create the falling snow, I used the old trick of diluting the paint (with medium and water) and splattered the piece with this mixture and a toothbrush. This technique accomplished the goal and brought back the only memory I have of Flagstaff and "near blizzard" conditions.
If you've never painted snow, it helps to know that it is much more than painting white out of the tube. That's generally considered a "no-no" and only whites with the tint of another color are used. Of course you can see that it looks like white, but the reality is that there are at least three or four different tints + white that created the snow. And there you have it...just a few more things to think about.