I just saw this and found it interesting.
Looking closely you can see that their turn-around circle did not burn and that a wooden wagon was spared as well. Fire is fickle. From the looks of things, in hindsite, the fire was relegated to the understory and may well have been defensable had the owners stayed...or could have become fatal if they had...no way to predict...
The fire was wind-whipped--60MPH gusts and carried forward by burning embers, so survival was not good and ability to keep the house would vary from minute to minute. No way of knowing. This is just one of those strange things that happen. My niece's neighborhood is gone--except the house on the corner. why??