Imaged by Ed Pina.
Cloud shadows, or their
rays, are one of the few
atmospheric optics effects that are "real".
They are real in the sense that they
are three-dimensional objects, they occupy
space, an aircraft
can fly through them. Halos, rainbows, glories and most other effects
are bundles of rays that meet your eye - they do not exist in space
and cannot be touched or looked at from another angle.
Cloud shadows are long columns of dark
air stretching away from the sun
from clouds. Sometimes, as here, the shadow tube intercepts
a lower cloud layer and blocks that too from the sun.
Image ©Ed Pina, shown with