lol It's just a severe thunderstorm, though it would work brilliantly for a forest fire manip.
It gets it's color because of the way the light hit it. We get a lot of crazy colored cloud formations in Southwest Missouri, big ones too. I have pink and purple clouds in my gallery, and a few shots from the storm system that produced the F-5 tornado that hit Joplin. That was a freaky storm.. when the sunset started to peek through the clouds it literally looked like the sky was on fire. Mom has a knack for getting the right angle and framing when she takes photos of clouds.
She's way better than I am at it. Hopefully I can badger her into posting more soon.