Also, please evacuate when those orders are issued. It's hard enough dealing with a raging inferno, firefighters and rescue personnel shouldn't have to deal with idiots deciding they can fend off a fast-moving wall of 80-100 foot flames. No offense to any beloved idiots on my f-list who have done just that. I still love you.
Lots of reason create the perfect firestorm. We're in our third year of a drought. We plant homes in the middle of terrain that is very nice and private but also very difficult to access with fire vehicles. And then we do not let nature take its course when fires are sparked by lighting. I'm not saying to let homes burn, but these are situations created and exacerbated by humans (as usual).