It is a plot of color versus altitude (vertically) and season (horizontally), for the San Francisco Peaks, with January on the left and December on the right. Unchanging ponderosas down low and spruce/fir trees up high, with a belt of meadows and aspens, at mid level, which change color with the seasons. At the top is the bare rock above the treeline. White vertical streaks are snow left by individual snowstorms, which lingers longer at higher elevations and become more patchy with time, and also remains visible for longer in the meadows than in the trees. The two white vertical streaks in midsummer are whitening of the summits due to hail from summer thunderstorms.
As mentioned in one of the clues, this isn't a "real" image- I drew it with Corel Photo-Paint. Because of atmospheric and lighting variability, it would be hard to make this image from real data- to do it correctly would require nightly helicopter flights up the mountain with a searchlight, a high-speed multicolor photometer, and a GPS receiver.
We will present Andy with his prize at the party on Friday.
Thanks for everyone's interest!