What is this?

10/9/11

The Mark of Zorro Mystery Cloud

I don’t know what caused this formation,
almost like an airport in the sky.

The sun was shining from just above the mountains to the east
behind me and to the right a bit),
and lit this thing up.

The cloud formation appeared to be just a few thousand feet up —
too low to be contrail caused, I would think.

I stopped an airport maintenance worker to get his opinion.
He couldn’t explain it either,
but thanked me for pointing it out to him.