Impressive photo from the Sacata Fire

It took me a few seconds to figure out what I was seeing in this very interesting photo taken by Marta Kroger at the Sacata Fire. It appears to be the shadow of a fire lookout tower projected onto smoke, presumably from the fire, and probably very late in the day or just after sunrise. But I’m at a loss to explain the rainbow effect around the shadow. It’s almost like the tower acted as a prism.

The fire is on the Sierra National Forest 26 air miles northeast of Fresno, California. More information about the fire is here.