LOL - that was a nasty debate yesterday around here. Officially - today - the winds were in the high Cat 4 range. However, as we know, it took ten years for Andrew to be classified Cat 5, and Katrina certainly had Cat 5 storm surge.
I'm comfortable that Katrina will ultimately be classified Cat 5 at landfall.
Keep in mind that there were two landfalls: Plaquemines Parish in Louisiana and Bay St Louis in Mississippi. So, there are two different strengths, depending. It is officially classified as a Cat 4 in Plaquemines and a Cat 3 on the MS coast.
4.99
Hasn't the post-storm evidence shown that it was a Cat 3 storm surge, and that the flooding was from levee breeches that were lower than overtopping levels? E.g., debris ring levels are below the levee tops.