What would have happened if the Los Angeles fires would have been left unchecked?

I hope this doesn't sound like a strange question;I certainly wouldn't want to see this happen.But what would occur if the wildfires currently raging in Los Angeles would not have would not have been fought by a single firefighter?In other words,what if the blazes would have been left alone to do what they will?Would the fires eventually burn out on their own or would they eventually engulf the entire state?