We drove down to Venice, which is near the mouth of the mississippi, at the southern end of a long peninsula. As we got further south the land got lower and lower, and the sea closer and closer. At Venice the port is only half a metre above sea level. We kept thinking that when Hurricane Katrina hit, it had a 6 metre storm surge in front of it, which would have put this whole area under water. Many buildings are elevated on stilts, and we went past the new High School, which is being built all elevated.
When we returned to New Orleans we visited the Lower Ninth Ward, which was the area most affected by flooding from the failure of the levees. The Lower Ninth Ward is mostly abandoned. There are boarded up shops, and at least half the houses are boarded up and abandoned.
There is a good explanation of what the various numbers and letters mean here
Thunderstorm and Tornado warnings while we are staying in New Orleans