Look deeply into shadows on snow. You will see beautiful blues and violets. Don’t be timid about adding these colors over snow. What a delight. Shadows on snow show the contours of snowdrifts. Pay attention to the way the angles change as the shadows move across the drifts. The shadows reveal the shape of the surface of the snow.
Tree shadows in a stream bed. Observe the way the angle of the shadows change as they move across an uneven surface. Photo by Chris Czajkowski. http://wildernessdweller.ca
As you walk through a winter woodland, sketch those things that interest you the most. This may seem obvious but there is a tendency to take on much broader subjects than that which calls you. If you are interested in the shadows in the snow, draw the shadows in the snow, not the shadows, the trees, the distant mountains, and the clouds.
Click on the first image to start a step-by-step annotated slideshow on how to paint shadows in the snow with watercolor.
Start with a light pencil drawing of your subject. Here the trunks of aspen trees in the snow. Notice that as the trees move emerge further in the background, they are both narrower and higher in the picture plane (closer to the top).
Copy the patterns on the tree bark as accurately as you can, There is not “generic tree bark” texture. Each species has its own character.
Now punch in bold shadows on the snow. Do not be afraid of using color. Observe how changes in the angle of the shadows suggest changes in the slope. The dark area in the top left helps add contrast, brightening the snow.
Add a hint of yellow ochre to the trunks. Aspens have a layer of chlorophyl below the light bark that gives a tint to the trunks.
Push the contrast of the dark marks on the trunks. Notice how this helps the tree read as white even though there is a lot of color on the trunks. Also notice that the distant trunks are handled more lightly and with less detail and contrast.