On balance, the analysis of the path of Katrina shows that, in the final few hours, the hurricane veered away from downtown New Orleans, heading actually slightly northeast toward Mississippi where most people had evacuated or had trees to climb.  The storm tide in Mississippi was typically 20-32 feet (10-m) high after 4 hours, gutting 3rd-floor rooms, while in New Orleans, the tide was less than 7 feet (2 m) from being on the weak (west) side of the eye-path.  The levee system, raised to 23-feet high, would have been swamped 8 feet under by the Mississippi tide that flooded 12 miles inland.

Also, just before landfall, Katrina's eyewall replacement cycle miraculously reduced wind-speed from a Hurricane-Camille force down to only 125 mph (200 km/h), which might have shattered most windows in the French Quarter, but the wind subsided.  The 50,000 left in New Orleans could have faced a gushing sea of broken glass, but instead, saw slowly rising water for days, and had time to leave or wait for evacuation help from FEMA.

Although Katrina's reduced winds might seem like a made-for-NOLA miracle, many hurricanes have undergone a similar eyewall replacement cycle as winds slow suddenly when a hurricane approaches a wide land mass.