A Storm For A New Climate?

Alexander S. Kolker, PhD.

In the wake of Hurricane Ida, we will inevitably hear comparisons to Hurricane Katrina. I will start off by saying that I do not think this comparison fair on a personal level. For every family that lost a loved one, for every business that lost years of hard work, for everyone who lost a home with cherished memories, each storm was a tragedy. A lot of people lost a lot of irreplaceable things, and we need to keep this in mind as we discuss these difficult events.

            However, comparing the two storms does give us some insights into how we manage and live on this coast in a changing world. And there are important differences between the two storms. Hurricane Katrina’s impacts in Louisiana were largely the result of structural, environmental, and engineering deficiencies that were followed by massive governmental incompetence.  In Hurricane Ida, the impacts come from a massive storm that produced impacts that were beyond the specifications of systems in place. In Katrina, the levees failed because they were not built to the standards they should have been designed to. In Ida, multiple systems failed largely because the storm’s impacts exceeded our expectations for what infrastructure should withstand.

Hurricane Ida from space on August 29, 2021, with Louisiana’s coastline added for reference. Image source: NASA.

            To recap, Katrina was a powerful storm that made two landfalls, the first near the mouth of the Mississippi River, and the second near Bay St Louis, Mississippi. New Orleans was on the west side of the storm, which is the weaker side. Despite this, there were massive levee failures in the city. In the lower 9th Ward, surge from the industrial canal burst a poorly constructed levee in along the industrial canal. East of here, the wetlands buffer that could have reduced Katrina’s storm surge had been lost, a result large-scale human-induced changes to the coast. Additionally, storm surge in Lake Pontchartrain backed up drainage canals causing them to collapse, and flooding much of central New Orleans. In Katrina, the levees failed because they were poorly designed, poorly constructed, and poorly maintained. This was followed by response that included incompetence of the highest order.

The Lake Borgne Surge Barrier, the white line in the foreground, is a 1.8 mile long, 25 ft high barrier that is part of the post-Katrina flood risk-reduction system that surrounds the New Orleans metropolitan area. Image Source: A Kolker with thanks to Southwings.

            One of the most important lessons Louisiana learned from Katrina was to build better structures and better systems. The Army Corps built a stronger levee system around the New Orleans metropolitan area. Louisiana created an organization dedicated to managing coastal assets, which developed a science-based plan to rebuild wetlands and construct levees. The Federal Emergency Management Agency developed better tactics to respond to storms. Elected officials realized that an incompetent response to a storm was a career ender. Louisiana’s post Katrina coast is far from perfect, but there has been a substantial effort to rectify the problems that caused that disaster.

            Ida was different. Not only was it among the most powerful storms to hit Louisiana in recorded history, but it stayed a powerful storm once it came ashore. Ida remained a Category 4 storm for 4 hours after landfall, a category 3 storm for an additional 4 hours, and a hurricane for at least twelve hours after making landfall.  This is unusual. Hurricanes often loose power quickly when they hit the shore, and it is not uncommon for them to begin to deteriorate before they make landfall. Ida likely stayed strong because it drew energy from the coast – either from Louisiana’s coastal bays- many of which had water temperatures above 90oC before the storm, or from swampy soils. Hurricane force winds extended out over nearly 100 miles and winds over 120 miles per hour extended over an area of nearly 50 miles. A map of wind gusts from Ida shows intense winds covering much of the southeastern portion of Louisiana.

Map of gust wind fields during Hurricane Ida. Source: ARA and National Institute of Standards as noted.

            The intense winds help explain why so many systems collapsed during Ida. The power system collapsed because of what the power company called, “Massive Transmission Failure.” This included, most famously, a large transmission tower that collapsed into the Mississippi River, but numerous poles, transformers and powerlines also failed across the state. Homes and businesses have been unable to operate generators because the fuel system collapsed. Oil refineries were damaged, and gas pumps did not have the power to operate. Paying for gas is hard because the parts of the internet were down, so you can’t run a credit card or go to an ATM. While these problems are beginning to clear up in some urban areas, they still exist in many places in Ida’s path.

            In Bayou Country, the housing system is stressed because winds damaged so many homes. This includes Houma, a town of about 35,000 is roughly 30 miles inland that had been thought of as a relatively safe place during storms. The economy is under stress, because many of the businesses that service offshore oil rigs are near Houma, and they too suffered damage. While there are not many people on the road in Houma, traffic can be a problem because many signals are down.

Damaged power pole in the town of Cocodrie, Louisiana, which is about 30 miles south of the city of Houma. Image source: A Kolker.

            Like Katrina, Ida revealed the weakness of various systems – in particular the energy and power system.  But the damage from Ida was so extensive because it was powerful and stayed so after coming ashore- it even flooded the New York City subway. Ida wasn’t exactly a one-off either. Hurricane Laura, which was nearly as powerful, hit Lake Charles a year earlier.

            Moving forward, what does this mean? It means we have to design our society for extreme conditions. We have to assume that the average weather conditions we can expect- the climate – is fundamentally different from what Louisianans experienced in last century. This impacts everything from the engineering standards we use to design our infrastructure to the assumptions we make about which communities are safe from storms.           

While the climate has changed fundamentally changed, we should not take this lying down. The climate is changing because there are more heat trapping gases, like carbon dioxide and methane, in our atmosphere. Acting together with people across the world, we can change our climate pathway. By releasing fewer heat trapping gases, and doing more to remove those already in the atmosphere, we can slow this warming. If we try really hard, we might be able improve our climate situation. Or we can choose to continue to increase the amount of these gases we emit, accelerating the problem. The first option won’t be easy, but right now it seems a lot better than putting up with another event like Ida.

A gas station outside of Houma, Louisiana, which was impacted during Hurricane Ida. Image source: A. Kolker.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s