[jyl]

When I lived in So Cal during late '80s and '90s (two earthquakes, LA riots, Malibu fires, etc), we were careful to have about 30 gals of bottled water, canned food for several weeks, the cooking and first aid stuff that went along with being active backpackers, and lots of guns. We've been lax up here in No Cal, but still had around 10 gal water and canned food for a couple of weeks, though we might have had to eat it cold. We're going to return to our So Cal levels of preparedness.

No doubt many of the people who didn't evacuate New Orleans failed to have adequate emergency supplies, just as plenty of So Cal and No Cal residents still don't have earthquake kits. But it's probably unlikely most people's emergency supplies would still be useful when their house was under turbid brown water to the roofline.