6. Looking upwind at a lee-wave
cloud (foreground), Boulder, Colorado.
Stacks of lenticular clouds give the band a bumpy appearance.
In the distance is a wave cloud
band capping the Continental Divide,
which is the main orographic
barrier.
The mountains in the foreground,
which appear larger in the
photo, are actually smaller foothills.
(Photo courtesy of Dale R.
Durran.)