Fringed Hill Shadow
A low evening sun shines here and there through rain clouds dripping fall streaks. The hills are backlit. At right the shadowed hill has peculiar fringes echoing its profile.
Imaged by Ed MacKerrow (Photography) in Southern Colorado near the New Mexico border.
All images ©Ed MacKerrow, shown with permission
Catch you optics quickly, camera always at the ready.
The effect was brief. In this image, taken less than a minute earlier, we see a 'normal' view of rain lit sunlight filtering between the hills.
The fall streaks are very evident.
Sheets of falling rain are everywhere. Near the hills they are in sunlight. The raindrops refract light towards the camera as part of the zero order glow.
Each discrete rain sheet between the hill and camera acts as a translucent screen.
Drops above the hill's shadow shine bright to form a profile of its rim.
The closest sheets intersect the shadow lower down to make a series of overlapping hill profiles. All of them below the actual hill's rim.
BUT - If the camera was closer to the hill and inside its shadow the rain sheet generated profiles would be above the hill. Layers of mist act similarly.