A 'forest fire/camp fire' should not get hot enough to burn brick/stone but 51 seconds into this video we can see that the front of the building is gone. Also in the next shot of the McDonnalds, I think that if a building (that contains frying grease) would get hot enough to melt a plastic sign a few feet away (or at least visibly warp the sign), but it does not look like it cinged (scorched) the grass.
I have heared that perhaps certain people wanted all that property to be burnt.
