Re: “Here's why the Mississippi River won't pose the same dangers as last hurricane season,” by Tristan Baurick
As Louisiana begins another hurricane season, we must always remain aware of the potential impact that the powerful and rapidly changing Mississippi River can have on our region.
For the second consecutive year, Louisiana has seen an early-season storm surge propel up the Mississippi River. While river levels in New Orleans are approximately 2.5 feet lower than at the same time last year, to conclude that the Mississippi River is less of a factor during this or any other hurricane season because levels have fallen is incorrect.
To understand the flooding our region could face during hurricane season, we must consider other factors in addition to river levels, such as storm surge, intensity and track. Every storm has a unique set of conditions that will result in various effects on our region. Past hurricanes have pushed storm surges up the river during low water and raised water heights between the levees by as much as 12 feet. During Isaac, the Mississippi River at Belle Chasse flowed backward briefly.
The Lake Pontchartrain Basin Foundation, a leader in scientific research, education and advocacy for more than 30 years, released two studies that analyzed time-lapse surge movement for Hurricane Katrina, which tracked east of Lake Pontchartrain, and Hurricane Isaac, which tracked west of the lake. While these storms were fundamentally different in terms of intensity and track, both resulted in surge building in the same areas, causing catastrophic flooding.
Another important aspect of surge movement is that severe flooding can occur when surge is moving back into the Gulf of Mexico. It is generally implied that the surge moving inland is of greatest concern, however, “outflow surge” events have been devastating and continue to present a sizable threat to multiple regions. For major hurricanes like Katrina and Camille, outflow surge interacted with the Mississippi River and overtopped the river levees on both the east and west banks during low water of the river, and devastated lower Plaquemines Parish twice.
Because of these compounding factors, it’s irresponsible to discount the Mississippi River as a threat to our region during hurricane season, even during low river stage. LPBF encourages the public to review these reports, as they reveal critical information about the risks of storm surge. It’s also important to remember that every storm is different. To ensure our safety, we should all err on the side of caution and follow emergency directives during a storm event.
executive director, Lake Pontchartrain Basin Foundation