Flood — East Baton Rouge, Louisiana

2016-08-13 to 2016-08-20 · near Plains, East Baton Rouge, Louisiana

Event narrative

Twenty to thirty inches of rainfall over a 2 day period led to widespread flash flooding in East Baton Rouge Parish, details of which are contained in the flash flood report for the parish. As water drained into the local rivers, record levels were recorded along the Amite and Comite Rivers, with flooding far exceeding the 1% annual risk flood plain. Portions of interstates 10 and 12 were closed due to high water on the roadways as crests moved downstream. In all, approximately 25,000 homes and hundreds of additional businesses suffered various degrees of flooding, though it's difficult to determine how many were due to initial flash flooding and how many were due to subsequent river flooding. Due to the extremely high water levels on the Amite river, water flowed back upstream on many streams and bayous, leading to a significant back water flooding problem. Much of the flooding in the southern part of the parish was due to this back water flooding. The end time of the flood is based on when Bayou Manchac near Little Prairie dropped below flood stage. However, some back water flooding continued on the Bluff Swamp for several more days. Four fatalities are attributed to the flooding. A 58 year old man drowned near the Mallard Lakes subdivision off Hoo Shoo Too Rd, likely some time the morning of Sunday 8/14. He was last seen late Saturday night riding a 4-wheeler. A 63 year old woman drowned the afternoon of Sunday 8/14 when her vehicle was swept away while trying to turn around in flood waters near the intersection of North Ridge Dr. and Hwy 423. A 55 year old man drowned in the Sherwood Forrest area, likely some time Sunday 8/14 or Monday 8/15, possibly after falling off the top of his mobile home where he was planning to wait out the flood according to a news media report. A 57 year old man drowned in the Greenwell Spring area, some time Sunday 8/14 or Monday 8/15.

Wider weather episode

A slow moving low pressure system brought widespread showers and thunderstorms to the area. The system tapped into deep tropical moisture resulting in very intense rainfall across a large portion of the area. Two-day rainfall totals of 10 inches or more were common across areas generally to the west and northwest of Lakes Pontchartrain and Maurepas. The heaviest rainfall occurred across a swath of East Baton Rouge, Livingston, and St. Helena Parishes, where 20 to 30 inches fell over a 48-hour period, topping the 0.1% annual exceedance probability. The heavy rainfall led to widespread flash flooding and record river flooding. Many of the broken records had been set during the flooding of April 1983. In total, 12 people died in southeast Louisiana as a result of the flooding. The event was also responsible for an estimated total of ten billion dollars in damage across southern Louisiana and southern Mississippi. This estimate includes impacts of both the initial flash flooding and the resultant river flooding.

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Source: NOAA Storm Events Database, event_id 656856. Narrative written by the NWS forecast office that issued the report.