I heard it on NBC this morning that he got separated from his hunting party and set off something to signal his position. I doubt a hunter in a high risk fire area where a campfire is banned would do such a thing.
Another version is being widely reported: that the cause of the Cedar Fire in SD Co. was a signal flare launched by the lost hunter.
It is not obvious that a signal flare will come down to earth burning. And they sell them in catalogs and stores, so it is possible a hunter might carry one.