The red you see in about the middle of the pic below is my roof. I'm surrounded by hills. The area in the foreground burned, the area in the background beyond the house burned about 10 years ago.
In the 14 years I've lived here, every fire (five of them) started on the other side of the hill on the I-5 freeway. Shown in the pic below. All are believed to have been tossed butts, plus one car fire. Most of what you see in the pic below is my property, facing the freeway. Not useful property, but I have a huge hill between me and the I-5. In the backyard, you can't hear the freeway noise at all. The hill between me and the freeway is about 500 feet in height.