Tom's motivation to “record” this particular observation was the first significant snowfall of the winter. The image below was taken of a similar snowfall within a forest. If you compare the portion of the photo outlined in blue to Tom’s plein air sketch, you will be amazed at the accuracy of his observation. Tom would have been painting after the first cold Arctic outbreak of the season in the wake of a strong low pressure area. Shadows do not play a role in Tom’s painting and the viewing angle is not really important. He was simply standing on the edge of a forest.