FWIW, I saw a fire that looked like it was burning on top of flood water. A nat gas leak that torched off? Situations like that would have to be a major concern for folks doing boat rescues.
I think gas lines are ruptured. I saw the same bubbling water and assumed it was a sewer spewing froma manhole opening. Now that it's on fire, clearly it's a natural gas main broken, and burning.
I expect that even once you spend months repairing the levees and draining the city, it will take years to repair all of the damaged infrastructure. Gas, power, water, sewer, telephone....all ruined by the water.
Yes, those are ruptured natural gas lines. When you look at the aerial footage, you will often see white, round, bubbling areas. That is the gas escaping - and if it ignites, there is nothing to turn it off.
There are many, many houses burning. At least one advantage to having a lot of water around is that the fires don't seem to spread a great deal locally.
What it does mean is that the gas pipelines will have to be shut off to all the flooded parishes once the levee breakages have been patched. If too much water is pumped while the gas is still flowing, the fires can spread.
I heard a report that there was gasoline floating on top of the water in some areas. It would be a hellish irony to have fire damage on top of flooding.