If all does not go well this weekend, Tropical Storm Barry will spin into the city of New Orleans, bringing with it (according to the National Oceanic and Atmospheric Administration) life-threatening storm surge, 40 mile-per-hour winds, and perhaps as much as 25 inches of rain. Barry is a lumbering brute; forecasters expect it to linger. Early coverage of the oncoming storm has focused, understandably, on the seemingly tenuous state of the levees alongside the Mississippi River.