The same snow was duplicated, warped , etc. to work with the individual boxes. There were some curve adjustment and cloning & airbrushing too. Too much to bother detailing here.
step 8 of 9
The cardinal was added for life and color. Saturation and levels were tweaked for the scene.
step 9 of 9
Shadows were added from the cardinal, & some were drawn on the box-snow from the tree out of sight to the left rear. BTW, I forgot to mention the 1st box was removed early on & I made a board from existing elements in the source.