We had a circumhorizon arc here 2 weeks ago. Apparently it's one of the most unusual appearences in the sky, like - ever. Look it up, it's hella cool. All the one's I found on the interweb were nothing like what I saw here.
That must not be so uncommon there. My mom lives just out of cedar rapids, and she sent me an email the other day of the same thing.
the 1st one looks like the underside of a gust front which is the leading part of a thunderstorm, the 2nd looks to be Altostratus opacus and Altocumulus stratiform opacus mamma
Many times <A BORDER="0" HREF="http://www.supercars.net/PitLane?displayFAQ=y"><IMG BORDER="0" SRC="pitlane/emoticons/smile.gif"></A>. Beautiful shots of those warped mammatmus. I wish I took a picture on the really windy/semi clear day we had a while ago, the clouds were so windswept it was nuts.
Clouds are sweet. It's too bad people don't look up anymore to appreciate them. I see those rainbow clouds when I drive on the 407.