Good point. I think the water surge is going to be a factor, because we have already seen so many examples of the water simply moving through and taking everything with it. The same kinds of things happened in 1993 during the 500 year flood.
The Biloxi-Gulfport area appears to be ground-zero, and that is probably where we are going to see the highest death toll. Reports say the water traveled several miles inland, so for all we know that is where the above mentioned, happened.
Whether the dead are suspended in trees or buried under debris is irrelevant. It only matters that people have died, a number which we don't yet know.
There are a few sources hinting at a large death toll today. This was posted by Rod Dreher on National Review Online last evening:
BODIES, LOOTERS [Rod Dreher]
I finally got through to my family down in south Louisiana today. They live just north of Baton Rouge, on high ground, and had no damage, other than fallen trees. But they have no power, and don't know when they'll get it back, so they're boiling in the late August heat and humidity.
Still, my sister said they would never complain, given what people are suffering not too far away. She had little idea of what's happening, because their TVs don't work. It's probably just as well. I heard from a Louisiana National Guard source that there are bodies everywhere in the far south, but the authorities aren't publicizing this.
I don't know if that means "thousands" dead, but, given Gov. Barbour's remarks last evening and this morning, it would be no surprise.