The fire and comments from the girl seem a bit suspicious. She said that she had quit smoking, but her friend had left at 8am and may have dropped a cigarette when he left. I guess it's possible that it sat there under the porch and smoldered all day before catching the porch on fire, but who knows.
As far as getting the upper hand on the fire with gravel, I have to give that credit to the two years I spent fighting fires as a LA County Camp 9-1 helitack fire suppression crew member. When they drop you off with the helicopter at the head of a brushfire, you don't have access to water. You remove the fuel (brush) and throw lots of shovel loads of dirt on the fire line to smother it. We spent a lot of time training as a crew, suppressing oil fueled fires. We actually did it as a competition between crews.
I didn't have any dirt, so I used the next best thing I had on hand, caliche roadbase. I had to "throw" it under the porch cover with the bucket while also hitting the patio supports burning about 8 feet high. All these years of learning how to use the machine as an extension of my hands, control material in the bucket, including throwing it out in front of the machine paid off.
Eddie - My wife is an amazing person. I give her all the credit for saving this girl's life. I don't know if we could have gotten the upper hand on the fire if we had arrived five minutes later.