Flood — Tangipahoa, Louisiana

2016-08-13 to 2016-08-16 · near Greenlaw, Tangipahoa, Louisiana

Event narrative

Twelve to eighteen inches of rainfall over a 2 day period led to widespread flash flooding across the northwestern half of Tangipahoa Parish, details of which are contained in the flash flood report for the parish. As water drained into the local rivers, major to record flooding occurred along the Tangipahoa River. Flooding far exceeded the 1% annual risk flood plain. Interstate 55 was closed from exit 50 to exit 53 between Fluker and Arcola due to water over the roadway. Additionally, the entirety of Interstate 12 through Tangipahoa Parish was closed as flood crests on both the Tangipahoa and Natalbany Rivers pushed high water onto the roadway. The end time of the event is based on when the Tangipahoa River near Robert dropped below moderate flood stage, though minor lowland flooding continued beyond this date. In all, 11,000 homes and businesses suffered various degrees of flooding throughout the parish, though it's difficult to determine how many were due to initial flash flooding and how many were due to subsequent river flooding. One fatality is attributed to the river flooding. A 20 year old woman was found drowned in her vehicle in the Cherokee Beach area where Hwy 442 crosses the Tangipahoa River.

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.

View location on OpenStreetMap → (31.0000, -90.4760)

Source: NOAA Storm Events Database, event_id 656675. Narrative written by the NWS forecast office that issued the report.