The Mississippi River at Baton Rouge, LA had been in major flood stage for 148 days…until Wednesday. On July 24th, 2019 the river level at Baton Rouge dropped below the 40 foot level. Above 40 feet is major flood stage. Below 40 feet is moderate flood stage, until 38 feet (and below) which is minor flood stage. Any level below 35 feet is under the flood stage mark.
The reason this is impressive is that it shatters the previous record for prolonged flooding of the Mississippi River at Baton Rouge. As of Thursday, July 25th the river at Baton Rouge had been in flood stage for a consecutive 201 days! The previous-longest flood stretch was 135 straight days back in 1927, according to the National Weather Service office in New Orleans.
We would love to impress you with all of the statistics about this flooding event, but we don’t want to steal the show. NWS New Orleans provided an in-depth Twitter thread on the subject. We’d like to thank them for the information and show you their tweets:
148: Number of days the river has spent at/above "major" flood stage at Baton Rouge.😮
(It fell to 39.98 ft on April 17 but was back above 40 ft for the observation taken 15 minutes later.)
It fell below 40 ft this morning and is expected to continue falling!
(2/12) pic.twitter.com/OAjPR6EjaO
— NWS New Orleans (@NWSNewOrleans) July 24, 2019
To understand why the flood has been so long lasting, let's take a look at its history…
This flood is really the result of several heavy rain/flood events with bad timing. Looking at the hydrograph trace, we can see at least 5 distinct rises. #lawx
(4/12) pic.twitter.com/cyw7psswRl
— NWS New Orleans (@NWSNewOrleans) July 24, 2019
Before looking at some of those rainfall events, let's look at the massive area that drains into the Mississippi River. Over 40% of the contiguous US – including 4 other major river basins (Ohio, Missouri, Arkansas/White, and Red) – drains into Mississippi River! #lawx
(6/12) pic.twitter.com/ntXA8Noo1c
— NWS New Orleans (@NWSNewOrleans) July 24, 2019
The second rise was mainly due to heavy rainfall stretching from northern MS through southeastern KY in February and early March. During the month of February a large portion of that area received 10 to 20 inches of rain, which is 300-400% of normal! #lawx
(8/12) pic.twitter.com/rj1ICfLMkR
— NWS New Orleans (@NWSNewOrleans) July 24, 2019
The final rise (which was more gradual and almost more of a steadying out) can mainly be attributed to more widespread rainfall across the basin, but there was a swath of 10-15 inches across parts of the OH/TN Valley. #lawx
(10/12) pic.twitter.com/0ilqAtrCZK
— NWS New Orleans (@NWSNewOrleans) July 24, 2019
But there's a light at the end of the flood tunnel! The river is currently forecast to continue falling and should finally drop below flood stage (35ft) again some time around August 5.
(Note: All stages/dates mentioned in this thread are preliminary & subject to change)
End. pic.twitter.com/5Q5g8yAIxi
— NWS New Orleans (@NWSNewOrleans) July 24, 2019
Twitter threat courtesy NWS New Orleans on Twitter
For WeatherNation, Meteorologist Steve Glazier