POPULAR MECHANICS has been doing an in-depth investigation of the Katrina disaster, and posting reports to its blog in advance of a big forthcoming article. Here’s one:

To understand the full impact of Katrina, you have to make a distinction between New Orleans and the rest of the region. New Orleans suffered devastating inundation due to the various levee breaks, but wind damage was moderate. When you fly over the city, you see a patchwork of blue FEMA-supplied tarps on roofs. But the real damage came from below as floodwaters from failed levees rose and quietly soaked homes through and through. Only in areas where the levee failures were particularly sudden and intense—like the Industrial Canal and the 17th Street Levee—were houses physically demolished.

Outside the city you see a different story. We drove east out of the city on I-10, crossing over the famous twin-span bridge across Lake Ponchartrain. (Today it is a crowded single span as crews install temporary roadways across the destroyed portions of the northern span.) For the next eight hours we drove in a big loop through Slidell, Biloxi, Gulfport and Pass Christian. In all that time we never left a zone of hurricane destruction that ranged from moderate damage to total annihilation. And this is after three months of clean-up operations. . . .

Biloxi ought to be Exhibit A in any discussion of whether current coastal development regulations make sense. The beachfront properties were devastated, but only a few hundred yards inland, damage was moderate. Maybe there’s a lesson there for developers? Apparently not. Compared to New Orleans, where whole neighborhoods remain deserted, Biloxi is crawling with construction teams. Most of them are busy rebuilding hotels right at the water’s edge.

Read the whole thing, and scroll down the blog for other reports.

UPDATE: Reader Barry Dauphin emails:

I take some issue with the portrait painted by Popular Mechanics. I don’t dispute what they saw in Biloxi, etc. But they are under reporting the wind damage. There are lots of blue tarps all over the greater New Orleans area. Damaged roofs are not caused by flood waters. There is no question that the levee breaches were the cause of the most substantial damage and the reason the city is a semi-ghost town. But having been in New Orleans at Thanksgiving, I think Popular Mechanics is minimizing the damage from the storm other than flooding (I have pictures). The rest of what is written seems accurate.

And Mississippi reader Jane Meynardie emails:

I agree that floating casinos are stupid. But as for the notion that Biloxi ought to be Exhibit “A” for how not to develop a beachfront, I must protest. Many of the homes that were destroyed on Biloxi’s beach (and in Pass Christian, Gulfport and Bay St. Louis) were over 150 years old. (One in Bay St. Louis was over 200 years old and was built with axe-hewn wood prior to our first sawmill.) They took everything nature threw at them better and for longer than most of the crap that builders are putting up today under current codes (including our brand new $50+ million federal courthouse well off the beach). Many were built of cypress designed to withstand the water if it got wet. Beauvoir (the retirement home of Jefferson Davis, given to him by my great-aunt’s sister-in-law) survived this storm, although it took a battering, and still commands the beachfront. There was NOTHING wrong with those homes and nothing stupid about their location. Some acts of nature are simply too ferocious and too freakish for anything short of concrete pilings to withstand, and God help us if we turn that beautiful beachfront that He has given us into a wall of concrete condos. Biloxians and Biloxi’s architecture could teach the rest of the world a good bit about how to survive these things. We’ve been doing it for generations.

So noted.