Waking in the Desert to Anticrepuscular Shadows

Everyone should wake up in the Southern California desert once in awhile, especially during April. My first word upon waking is "ouch", but after recovering from sleeping on the ground, I can enjoy this type of sight:

The photo shows anti-crepuscular shadows converging on San Gorgonio (the white peak in the distance). It is common to see beams of light while looking toward the rising or setting sun -- these are called crepuscular rays. However, this is the second time I've photographed the anti-crepuscular effect -- e.g., shadows continuing to the vanishing point opposite the sun (also called the anti-solar point). The crepuscular effect comprises light rays, shadows or both. In the above photo, the ray would be the larger area between the shadows, but I can hardly call that a ray. Rather, I see only the anti-crepuscular shadows. I suspect that the conditions necessary to create the appearance of smaller light rays against a darker background are more rare than this.

jg