What kind of phenomena is this?

[Shane Lee]

Thanks everyone for your above and beyond effort in trying to tell me what is in the picture. I certainly wasn't going to fly my airplane underneath it to find out for sure! Since weather radar is at a premium in third-world countries, this generated a pilot report cautioning ATC to keep other aircraft out of the area for a while.

Oh, and as for the "top secret" document knock yourself out! I believe it says something to the effect of "flaps--50%, landing gear--down. I imagine wiki-leaks could make a killing on that one too. (no pun intended).