'Mini-tsunami': Levee blasted in bid to save town

David Carson  /  AP

An explosion lights up the night sky as the the U.S. Army Corps of Engineers blows an 11,000-foot hole in the Birds Point levee in Mississippi County, Mo., on Monday.

msnbc.com staff and news service reports msnbc.com staff and news service reports

updated 2 hours 49 minutes ago2011-05-03T09:38:37

WYATT, Mo. — The U.S. Army Corps of Engineers exploded a large section of a Mississippi River levee late on Monday in a desperate attempt to protect an Illinois town from rising floodwaters.

But questions remain about whether breaking open the levee would provide the relief needed, and how much water the blast would divert from the Mississippi River as more rain was forecast to fall on the region Tuesday.

The corps said the break in the Birds Point levee would help tiny Cairo, Ill., by diverting up to 4 feet of water off the river. Just before Monday night's explosions, river levels at Cairo were at historic highs and creating pressure on the floodwall protecting the town.

The Ohio River at Cairo had climbed to more than 61 feet as of Monday.

For the Missouri side, the blasts were likely unleashing a muddy torrent into empty farm fields and around evacuated homes in Mississippi County.

Brief but bright orange flashes could be seen above the river as the explosions went off just after 10 p.m. The blasts lasted only about two seconds. Darkness kept reporters, who were more than a half mile off the river, from seeing how fast the water was moving into the farmland.

Seemingly endless rain
Engineers carried out the blast after spending hours pumping liquid explosives into the levee. More explosions were planned for overnight and midday Tuesday, though most of the damage was expected to be done by the first blast.

The seemingly endless rain has overwhelmed rivers and strained levees, including the one protecting Cairo, at the confluence of the Ohio and Mississippi rivers.

Accuweather's Alex Sosnowski said flooding caused by the relentless rain was set to get worse.

"The (lower Ohio and lower Mississippi rivers) region is about to turn into a vast lake that will linger not only days, but weeks due to the very slow-to-respond, massive rivers in a relatively flat part of the nation," he said.

Levels along parts of the Mississippi were expected to surpass records set in 1937, Sosnowski said.

Flooding concerns also were widespread in western Tennessee, where tributaries were backed up due to heavy rains and the bulging Mississippi River. Streets in suburban Memphis were blocked, and some 175 people filled a church gymnasium to brace for potential record flooding.

The break at Birds Point was expected to do little to ease the flood dangers there, Tennessee officials said.

The river was expected to crest late Wednesday or early Thursday at 63 feet — just a foot below the level that Cairo's floodwall is built to hold back — before starting a slow decline by Friday.

'Uncharted territories'
The high water has raised concerns about the strain on the floodwalls in Cairo and other cities. The agency has been weighing for days whether to blow open the Birds Point levee, which would inundate 130,000 acres of Missouri farmland.

Engineers believe sacrificing the levee could reduce the water levels at Cairo by about 4 feet in less than two days. Meteorologist Beverly Poole of the National Weather Service put the figure closer to five feet.

"These are uncharted territories, but it would be very fast," she said.

Paul Davis  /  The Daily American Republic via AP

Water flows over the Wappapello Lake emergency spillway on the St. Francis River in Wayne County, Mo., on Monday. Several roads have been closed in southeast Missouri after heavy overnight rains pushed lakes and streams out of their banks.

Carlin Bennett, the presiding Mississippi County commissioner, said he was told a 10- to 15-foot wall of water would come pouring through the breach. The demolition was expected to cover about 11,000 feet of the levee.

"Tell me what that's going to do to this area?" he said. "It's a mini-tsunami."

Maj. Gen. Michael Walsh — the man ultimately responsible for the decision to go through with the plan — has indicated that he may not stop there if blasting open the levee doesn't do the trick. In recent days, Walsh has said he might also make use of other downstream "floodways" — basins surrounded by levees that can intentionally be blown open to divert floodwaters.

Among those that could be tapped are the 58-year-old Morganza floodway near Morgan City, La., and the Bonnet Carre floodway about 30 miles north of New Orleans. The Morganza has been pressed into service just once, in 1973. The Bonnet Carre, which was christened in 1932 has been opened up nine times since 1937, the most recent in 2008.

"Making this decision is not easy or hard," Walsh said. "It's simply grave — because the decision leads to loss of property and livelihood, either in a floodway or in an area that was not designed to flood."

Officials in Louisiana and Mississippi are warning that the river could bring a surge of water unseen since the Great Mississippi Flood of 1927.

The corps has said about 241 miles of levees along the Mississippi River between Cape Girardeau, Mo., and the Gulf of Mexico need to be made taller or strengthened.

George Sills, a former Army Corps engineer and levee expert in Vicksburg, Miss., said the volume of water moving down the river would test the levee system south of Memphis into Louisiana.

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