They definitely weren't shadows. You could see the cloud begin to seperate and see the brilliant blue sky where cloud should've been. If you look the streaks are the exact color of the sky. This wasn't cloud shadows. This was the cloud actually being visibly split in a slow process until you could see the sky above it. Then it'd close up again and form in another spot.
That is a tremendous thunderhead in the shot. The only thing that I can figure is perhaps something was altered about that part of the atmosphere due to the storm?
Or aliens but we didn't see anything...
Stephanie
In every man there is something wherein I may learn of him, and in that I am his pupil.--Ralph Waldo Emerson