It helps when
1) Nature cooperates, and
2) The people in the area are too stupid to create firebreaks and put fire resistant roofs on their house.
Saw the same damn thing happen in Tahoe. People want their homes to be right up in the trees, so they fail to clear a firebreak, and then because they want the forest to remain "natural" (Hint: No such thing as a natural forest in the United States), they let underbrush build up, which creates fire ladders, which allows fires access to the crowns of trees, which makes the fire even larger than it normally would have been.
Southern california is the same thing, just without the trees. People want their homes right up next to the "wilderness" and so fail to create fire breaks, and then they stop natural fires, which causes a buildup of fuel (i.e. lots of thick vegetation, which in many cases is dead). Then you get massive fires that cause thousands to evacuate.
I'm really not feeling that much sympathy for those in Southern California right now.
