Plumb your roof for sprinklers! Before a fire gets close, turn the roof sprinklers on. Even on a very hot day, that will reduce the local temperature of the roof. If any embers land on the wet roof it is much more difficult for it to catch fire. If you have a pool, use a seperate fire pump for the sprinklers and the vegetation around the house. It isn't cheap; but, it is cheaper than dealing with the insurance company and getting less than full value for your home.