Brief diary to point out the flood event in the nation’s midsection.
Heavy rains from Christmas week have drained into the Mississippi, forcing it to rise substantially. This is a significant Mississippi River flood from about St. Louis southward.
This flood will last well into January. I’ve constructed a chart based on this site so you can know when the flood crest will pass your location, if you live anywhere along the Mississippi all the way to its mouth at the Gulf. The full chart is at the link. This chart is truncated.
| River Stage Forecasts | |||||||||
| Station | Flood Stage (ft) | 6pmStage | 12hr change | 30-Dec | 31-Dec | 1-Jan | 2-Jan | 3-Jan | Crest and Date |
Cape Girardeu | 32 | 43.8 | 1.7 | 45.1 | 47.2 | 48.3 | 48.2 | 48.5 | 48.5 01/02A |
Thebes | 33 | 42.8 | 1.8 | 43.8 | 46 | 47.2 | 47.4 | 47.4 | 47.5 01/02P |
New Madrid | 34 | 36.3 | 1.2 | 38 | 41 | 43.3 | 44.7 | 45.7 | 47.0 01/05A |
Memphis | 34 | 27.8 | 0.7 | 29 | 30.9 | 33.1 | 35.3 | 37.3 | 43.5 01/09A |
Baton Rouge | 35 | 31.5 | 0.1 | 31.8 | 32.3 | 32.7 | 33.2 | 33.8 | 44.0 01/19A |
New Orleans | 17 | 12.2 | -0.1 | 12.6 | 12.9 | 13.1 | 13.3 | 13.6 | 17.0 01/09A* |
LEVEES PROTECT CITY OF NEW ORLEANS TO 20 FT STAGE | |||||||||
(A)bove/(B)elow Flood Stage | |||||||||
*It is very likely the Army Corp will open a number of spillways above New Orleans metro to lower the flood crest as it passes the city, otherwise this crest will be on 1/20 at 17 feet. | |||||||||
This is just the Mississippi. The Ohio and the Arkansas, both of which empty into the Mississippi, are also both in flood, cresting not until early next week.
Jeff Masters writes:
On January 20, the flood crest is expected to arrive in New Orleans, bringing the Mississippi River to its 17-foot flood stage in the city, just 3 feet below the tops of the levees. In past years, though, when the river has been forecast to rise to 17 feet in the city, the Army Corps of Engineers has opened up the Bonnet Carre Spillway in St. Charles Parish, which diverts water into Lake Pontchartrain and keeps the river from reaching flood stage in New Orleans. The Corps may also be forced to open the Morganza Floodway in Pointe Coupee Parish, which would divert water down the Atchafalaya River. Opening this spillway has a considerably higher cost than opening the Bonnet Carre Spillway, due to the large amount of agricultural lands that would be flooded below the Morganza Floodway. The Corps also has the option of increasing the flow of Mississippi River water into the Atchafalaya at the Old River Control Structure in Concordia Parish
You can of course read all about Old River Control in this excerpt of Control of Nature by John McPhee, published in the New Yorker in 1987. Old River Control essentially keeps the Mississippi from changing its mouth, as the path to the Gulf is shorter and steeper via the Atchafalaya. Eventually, the river will win. Studies of the paleogeography of the US Gulf Coast show that the river’s got old mouths all over Southeast Louisiana, and its current mouth is only about 1,500 years old.
The Army Corp actually does know what level of flood will destroy Old River Control, wash Morgan City (which sits at the mouth of the Atchafalaya) into the Gulf and leave Baton Rouge and New Orleans on a fetid, salty swamp arm. You can read about it here. Luckily this flood, this time, does not appear to be the one.
I have concerns that this will not be the end of it. The atmosphere is giving signs that it will shift in the next couple weeks—the Great Pacific Warm Blob that killed so much sea life and influenced much of the weather for the last couple years across North America is finally dead and El Nino is locked in. It is going to get wet in southern California and the Southwest---and points east. Stay tuned.