The rhythm in this drawing is created by the geological movements in the land, the alternating black and white of snow and trees, and the play of light and shadow made spectacular by the presence of Cumulus congestus clouds and new snow.   The Wasatch Mountain Range has been growing at a rate of 1.5 ft per 1000 years (0.4mm per year) for the last three million years, and water drainages and weather have continued to erode the valleys downward even as the mountains continue their upward thrust. The folds of land shown on the right are a part of the Kelvin Formation that occurred during the Cretaceous Period over 66 million years ago.  

Like many artists I am captivated by the behaviors of light, including its absence (shadow). There are two types of shadow in the scene: light which has been absorbed by a dark object, such as a tree, and light which has not arrived because it has been blocked. The distinction between these two shadow states is easiest to see in the mountain left of center in the drawing. The cloud above blocks light from the sun and casts a shadow onto the mountainside. This causes a cool area, both in mood and in temperature. The trees growing here - Spruce, Douglas Fir, and Gamble Oak - are dark in color and absorb light, rather than having never gotten it. The charcoal mark too, like the shadow it represents, absorbs all wavelengths of light.  

These two distinct shadow types on blindingly smooth snow define the form in effortless rhythm, simple and complete. Charcoal on paper is the ideal medium for the subject of shadow and light, as it replicates the physical behavior of the light and darkness in that scene. Like the dark tree, the charcoal absorbs all wavelengths; like the snow, the paper reflects them. In one area light is absorbed and hoarded and in another it is bounced into the viewer's eye - the viewer of the mountain and the viewer of the drawing. The arrangement of these photons dances on the retina. In the presence of this beauty formed and forming over millions of years, the particular rhythm of the moment is rare and fleeting. All to our delight.