Why yes, that is a natural gas line running to the furnace and water heater: https://www.reddit.com/r/electricians/comments/1fpo26t/not_something_you_see_everyday_evidently_this/
Not something you see everyday. Evidently this image has gone a bit viral, but this is a friend of mines house. She hit me up wondering if I knew what might cause it. The flex was pulling about 175 amps and was at 1200 degrees. There's to be a whole news story on it and everything.
Mother of god, dare I say this post..... blew up. There are a lot of questions and there is no way I can get to everyone. Basically, during a storm a tree fell on the incoming lines and it caused some fucked up high voltage things and created a new ground.
I'm surprised the paper in a plastic bag, plywood floor, and cable casing aren't melting. It's starting to combust the warning labels but the floor should be on several kinds of fire.
Heat transfer is kind of like electricity transfer. It'll always travel the path of least resistance. It's the principle of the trick where you hold a lighter up to a super thin plastic water bottle or a balloon with water, the plastic won't melt until the water gets hot.