I'm not eliminating the idea of DEW… But… These fires are essentially blow torches. If they're wind driven or slope driven, there's not enough water in the world to stop them. Now picture a dude holding a flame thrower. He doesn't get burned but everything in front of him does… I've seen fire do gnarly things.
I've seen the pictures as well, but I always try to think of both sides of the coin. Natural or man-made… I'm more apt to believe it's bad people taking advantage of perfect fire conditions