The United States has faced devastating wildfires for many years. The recent rash of wildfires are no different from previous ones. These fires are due to development in places that are more prone to fires. The western United States has a much drier climate and has always been more susceptible to wildfires. In short, no, these fires are not because of global warming.
While many people have simply accepted global warming as a fact, is there really any proof. As any natural scientist or historian can tell you, the world has different sequences it goes through. For instance, when people get angry they overthrow a dictator and start a new government; eventually the same situation will be repeated. There is evidence to suggest that the earth has had periods of both cold and warm over the past ten thousand years.
The forest fires that are occurring are awful, but I don't think that they are the result of global warming. Instead, I blame humans. So many fires are caused because campers fail to completely put out their camp fires or smokers leave a cigarette butt somewhere they should not. People are to blame.
Global warming is not responsible for the rash of fires, it may however be a small factor. In fact, in the case of the San Gabriel mountains, the first fire was believed to have been started by a vehicle that had veered off the road. The conditions for the fire were made due to the heat and continuing drought, but in Southern California, this is quite common.