I believe that much of this area is not forest (trees), but grassland. This climate normal goes through periods of being very dry and very flammable. In that state, it doesn't take much for it to start burning.

That's true, at least by what I've seen on my visits there. I saw some of the damaged areas from the 2003 wildfires. There weren't many trees there. Mostly, I saw grassy fields with some brush. Grass and brush wildfires can spread extremely fast especially with those high winds spreading embers all over the place.