MISSISSIPPI RIVER FLOODING:  This is the AP wire story.  I don’t have much understanding of levees, rivers rising and cresting; I grew up in an arid region of California and have never lived near the great interior rivers, the Mississippi, the Missouri, or the Ohio River valley.  But our thoughts are with those in the downstream path.  Update: Given how little I know that geography, I am taking the liberty of posting a long email from someone who is actually there, and thanks for sending.  Posted below the fold.

“The AP story you linked over at Instapundit is badly written – the
sort of story written by one journo in Memphis and two in Jackson,
neither of whom actually went out there.

In the briefest telling, the Mississippi Delta – that big pale area on
the satellite views that covers NW Mississippi, SE Arkansas, and NE
Louisiana – is the enormously flat floodplain of the Mississippi
River. The land only falls 100 feet in 200 miles, so the rise is
usually imperceptible to the naked eye. Water accumulates slowly, and
it dissipates slowly – areas that flood will remain flooded throughout
much of this year’s growing season, and large floods in the past have
even hampered the next year’s crops. There are two serious concerns:

1. Levee breaks on the mainline Mississippi levee. A single,
continuous levee stretches from just below Memphis to the mouth of the
Yazoo River a few miles above Vicksburg. This levee does the hard work
of holding back the big river, and a break would be catastrophic – a
roughly 25-foot tall wall of water (the top of the levee at Greenville
is about 150 ft above sea level, while the surrounding land is in the
low 120s) would come crashing in, resulting in massive flooding and
loss of life and property.  The woman from Rena Lara is talking about
the failure of this levee. However, this is not the primary issue
worrying the state – all involved, while concerned, are more worried
about the action further south.

2. Flooding in the southern Delta from the Yazoo River. If you look at
Google Earth, you’ll notice that the southern regions of the area are
only about 90-100 feet above sea level, and that they have less
farmland and more bottomland (aka swamp) forest. Because the Yazoo
River is connected to the Mississippi, a flood on the big river will
eventually produce a flood on the Yazoo, either directly (by flowing
upriver) or indirectly (by preventing the Yazoo from flowing out). The
levees that exist along the Yazoo are smaller than the mainline
Mississippi levees, and a very few populated areas are not actually
protected by them –  immediately northwest of Satartia, Miss., is the
levee gap that allows some floodwaters in (see my Twitter post, with
photos from this past Sunday, at
[I’m taking out the twitter link as it doesn’t seem to be working, and I can’t seem to fix it.  But check out #commiskey at twitter for photos]. At
present, this flooding is only affecting a few people. However, at the
crest of the Mississippi, the Yazoo levees are expected to be
overtopped by flood waters. If this is all that occurs, damage will be
somewhat contained, as they are only expected to be overtopped by one
or two feet, and the rate of water entry will be merely bad. However,
if the levees fail, and water is able to flow in freely, every point
below 107 feet above sea level is expected to flood (the source of the
“107 feet of water” in the AP article).  This extends quite far north,
and would drown roughly the southern third of the Delta (just below a
line from Hollandale to Belzoni, if you’re inclined to look at a map).
This is the most likely disaster scenario.

Anyway, thought that might help you imagine the situation a bit
better. And I’m enjoying your guest-blogging.”