River stage
Mermentau, Mermentau River
- River level
- 2.20 ft
- Status
- Below flood stage
- 7-day change
- +0.09 ft
- Recent high
- 3.52 ft
- Recent low
- 1.85 ft
Last reported 2026-10-13 | NWS MRML1
- 30-day change
- +0.11 ft
- Average
- 2.46 ft
- Readings
- 120
- Data span
- 122 days
- Record crest
- 14.50 ft
In brief
The Mermentau River at Mermentau, LA read 2.20 ft on Oct 13, 2026, 1.80 ft below action stage. That is 0.11 ft higher than 30 days earlier.
Source: National Weather Service gauge MRML1
River level timeline
Stage threshold profile
Highest crests on record
| Rank | Crest | Date |
|---|---|---|
| 1 | 14.50 ft | 1940-08-07 |
| 2 | 10.68 ft | 2016-08-18 |
| 3 | 10.56 ft | 2013-01-15 |
| 4 | 9.47 ft | 1972-12-10 |
| 5 | 9.05 ft | 1977-04-25 |
| 6 | 8.96 ft | 2004-05-18 |
| 7 | 8.66 ft | 1941-06-02 |
| 8 | 8.61 ft | 2017-05-06 |
Flood crests recorded at this gauge by the National Weather Service.
What happens at each level
- 4.00 ft
Minor lowland flooding near the river will occur.
- 5.50 ft
A few recreational camps and residences are subject to flooding.
- 6.00 ft
Flooding of the shipyard begins. Portions of castex landing, la 3166, become flooded and impassable.
- 6.20 ft
The water reaches the roadway of the 13th Street bridge in the southern portion of mermentau.
- 8.50 ft
Some residential flooding in mermentau will occur. Operations at Gulf Island shipyard can be affected. U.S. Highway 90 west of mermentau is flooded and subject to being closed.
- 9.00 ft
Some residential flooding in and around mermentau will occur. U.S. 90 west of mermentau is closed. Operations at the shipyards are affected. Roads in the mermentau cove area are flooded and impassable. Some residences are subject to flooding along the river near lake arthur.
- 9.50 ft
Widespread major flooding will occur with residential flooding in and around mermentau to the lake arthur area. Numerous roads are inundated across a large area including u.S. 90, la 3166, la 1126, and la 92.
- 10.00 ft
Widespread flooding over a large area from Interstate 10 to Lake Arthur with numerous homes and roads flooded. The community of Morse will be inundated with water. Much of Estherwood will be inundated due to backwater flooding from Bayou Plaquemine. Areas around Gueydan will be inundated with water due to backwater flooding from Bayou Que de Tortue. Communities of Klondike and Lowery will experience flooding as well.
- 13.30 ft
Water reaches the roadway of the of U.S. 90 bridge east of Mermentau.
- 13.40 ft
The river is near its 100 year flood level. Most of the community of mermentau is inundated with flood waters.
Written by the local National Weather Service forecast office for this exact gauge.
Frequently asked questions
Is the Mermentau River flooding at Mermentau?
No. The Mermentau River at Mermentau is at 2.2 ft, 1.8 ft below action stage.
What is the flood stage at Mermentau?
The National Weather Service sets action stage 4 ft, minor flooding 4 ft, moderate flooding 6 ft and major flooding 8 ft.
What is the highest the Mermentau River has been at Mermentau?
The highest crest on record is 14.5 ft, on 1940-08-07.
Is the Mermentau River high or low right now at Mermentau?
At 2.2 ft it is higher than 44% of readings over the last 122 days.
Stage and flood information from the NOAA National Weather Service (gauge MRML1); daily history from the U.S. Geological Survey (site 08012150). Last reading 2026-10-13. For flood safety decisions always follow official National Weather Service warnings.