Hurricane Katrina was serious indeed. Since the City of New Orleans is 12 feet underwater already it has always been at risk. The storm surge from Hurricane Katrina went right over the barrier islands and the waves severely impacted the lake. It was also due to the massive rains that filled up the canal over flows and sent increased water up the canals. Meanwhile the Mississippi is on the high side and is now draining in its normal flow plus that of the Hurricane. Add this to the wind of the Cat.