I saw that. I wish the warning had been more specific. Such as "if you live in the 9th Ward and the storm surge is "x" the water will be "y" and you will be sitting on your roofs waiting for rescue. A direct hit will mean a storm surge of between "x" and "z".."
Perhaps streetcorner signposts should have been (or should in future be) marked with elevation--either a big red marker at sea level, or a big green marker at some standard height above sea level (say 6'). Then in areas where the red marker was 2' above the ground, a report of floods 2' above sea level would let people know that the water would be 4' above ground level.