Source of the photo
http://www.environmentalgraffiti.com/news-10-incredible-fire-rainbow-images
Author of the description
GK
Fire Rainbows: the clouds needed for these rare events have to be cirrus and at least 20,000 feet in the air, with just the right amount of ice crystals. The sun also has to hit the clouds at precisely 58 degrees.
Source of description
http://www.environmentalgraffiti.com/news-10-incredible-fire-rainbow-images