Hurricane Katrina Revisited

Hurricane Katrina Compared

As mentioned, if Neoguri hit any shoreline in the U.S., the amount of damage may have been much different. Hurricane Katrina hit the Gulf Coast region in August of 2005. Figure 5.8 shows a portion of the mainland shoreline of Biloxi, Mississippi before and after Hurricane Katrina hit the region. You will recall from the last module that we explored this region already, so here we will learn just a little bit more and be able to consider why Katrina was so devastating when Neoguri wasn't.

In August 2015, we recognized the 10th anniversary of Hurricane Katrina. Perhaps you watched or read some of the retrospective news articles about Katrina and her impacts all along the Gulf Coast, and especially in New Orleans. Despite the distance of time from that event, the impacts of that storm are still very real, very raw, and very emotional for the hundreds of thousands of individuals that faced Katrina's storm surge, hurricane-force winds, and heavy rains. To add insult to injury, many of these individuals would experience even more catastrophic impacts when the levees that were built to hold back the sea actually broke. The failed levee systems allowed billions of gallons of rain and seawater to flood hundreds of square blocks of the city and neighboring parishes. Once flooded, evacuees who had relocated to high ground were once again confronted with additional evacuation orders. For some, the evacuation orders became permanent because they had no home to come back to, no jobs to return to, and in many cases, no family to return there with. The reality is that the Gulf Coast has still not recovered from that event, and it is likely that it will have lasting effects for decades to come. So, how is it that this storm would become one of the most significant global storms in a century?

Scientists from NASA 's Goddard Space Flight Center have produced an excellent short video that explains both how and where the storm developed. where the storm went, and the types of hazards that resulted. Data from numerous weather satelites were compiled to produce these magnificent 3D animations that illustrate exactly what happened before, during, and after the storm. Additional details about Hurricane Katrina are shared at this NASA website.In the video you will notice the role of warm surface waters in the Gulf of Mexico as they contributed to increased rates of atmospheric uplift which resulted in strengthening the storm. You will also see how the bands of precipitation moved across the region and the distinct wind patterns that moved the storm over Florida, out into the Gulf and eventually steering it right toward eastern tip of the boot of Louisiana, and southern Mississippi. Storm generation processes are explored elsewhere in this module so make sure you revist NASA's video once you have completed the readings for the module. NOAA has produced a short summary of the meterologic impacts to support the video animations from NASA. This summary is titled: Extremely Powerful Hurricane Katrina Leaves a Historic Mark on the Northern Gulf Coast - A Killer Hurricane Our Country Will Never Forget

In order to better understand the full impact of the storm on New Orleans, we strongly recommend that you carefully study the map-based time-series evaluation of the impact of Hurricane Katrina as it came ashore. The Times Picayune Newspaper produced an excellent interactive module that tracks the flooding from levee and flood wall failures as they happened. Each scene includes pop-up dialogue boxes that will guide you through the storm. As you work through the scenes, play special attention to the areas that became flooded (shaded in blue) and the areas where levees were compromised and breached either due to poor construction and failure or surge levels that overtopped them. The maps and detail are incredible, but how much was actually affected? Thanks again to the Times-Picayune for another infographic that shows the actual standing floodwater levels that occurred as a result of the storm. Exactly how much water flooded areas like Gentilly and Lakeview on the southern shores of Lake Ponchartrain? How much water flooded the Lower 9th Ward where many of the casualties were sustained? In fact, after all was said and done, the only areas that sustained little flood damage or none at all were the uptown districts and areas located on and immediately adjacent to the natural levees formed as the banks of the Mississippi River.

So, although much news and emphasis was focused on New Orleans after the storm, as we learned in the last module, other areas sustained significant impacts as well. This includes Biloxi, Mississippi and her neighboring communities. In fact, as we also learned, the storm surge was actually even higher in southern Mississippi in the area of Pass Christian than it was in New Orleans. We previously established how geography and the funneling of water into Lake Pontchartrain and Biloxi Bay contributed to these high surge levels. But what about the winds? Wind speeds for Southeastern Louisiana were substantially higher.

Once the storm made its landfall across the boot, the counter-clockwise rotating storm lost connection with the warm surface waters of the gulf (its fuel source) and the storm itself began to fall apart because it was unable to maintain the necessary convection to produce the intense winds. Moreover, both ground-level, and upper-level wind shear acted to reduce the intensity, and within a few hours the hurricane was downgraded to tropical storm and eventually to depression-level status. Nevertheless the storm left a trail of destruction that cannot be imagined. Having the opportunity to visit the area following the storm to help provide relief and support to residents was incredibly and deeply impactful on this scientist. Pictures and videos on the news, when you are 100s to 1000s of miles away, as emotion-generating as they can be, do little to communicate the magnitude and completeness of destruction the region faced. Having walked on a sidewalk that formerly led to residence halls at the University of Southern Mississippi, or having stepped across the door sill plate to a home that no longer had its walls or roof, or walking up to a pile of rubbish and picking up a TV remote control and a child's doll caked in mud and salt... These, these are the activities that still haunt this author in ways that rock my foundational core. It is these types of experiences, some photos of which are below, that truly bring home the reason why this course was designed as is being taught to you. We hope in this module and others before it, that you were able to learn about the science of coastal processes and hazards, and gain an appreciation for how hazards like Katrina and the Sumatran tsunami have the capacity to do so much damage and take so many lives. Likewise, we hope that you will be able to, throughout the remaining modules, understand the societal consequences and some possible ways forward that reduce our risk, improve our resiliency, and ultimately provide for a safer, healthier, happier future.

As shown in the images, coastal infrastructure including piers, beach houses, roads, and numerous residences were severely impacted if not destroyed outright. The high winds, high water, and erosive waves pounded the coastline during the third landfall of Hurricane Katrina as it came ashore as a Category 3 hurricane. You will recall from the previous module that Hurricane Katrina's storm surge (as observed in the USGS's visualization tool) extended well beyond the shoreline. Figure 5.9, 5.10 and 5.11 are photographs from Gulf Park, Mississippi four years following Hurricane Katrina. Figure 5.9 shows students walking around a community left in ruins. Few, if any, homes were rebuilt even four years later. The student in the tree shows the height to which storm surge reached. Figures 5.10 and 5.11 were photos taken on the ground floor of a residence hall at the Gulf Park campus of the University of Southern Mississippi. Located at Long Beach, students had just moved into their residence halls at the outset of the fall semester when Hurricane Katrina hit. The buildings were inundated with over 4 meters of water; many doors and windows blew out. The contents of most of the rooms floated out, and when the storm waters receded, most rooms were filled with feet of sewage and sediment, and other debris. Although most of the trash was cleared, even four years later, when the photo was taken, the buildings had still not been repaired or demolished. The photo galleries on this University of Southern Mississippi page show many of the before and after photos and are incredibly poignant in telling the story of destruction (and recovery) this university experienced.

There is a video on wunderground.com that shows the storm tide height and wind field as it approached the Mississippi mainland.

For further thought:

Given what you know about Katrina (or have learned from this initial introduction), you might already be able to think about some reasons why an event like Typhoon Neoguri, if it hit the U.S., would have had significantly different outcomes. Do you think an event of similar scale would have produced more or less damage than it did in Okinawa, Japan? Why or why not? Can you be specific and identify some reasons now that might contribute to a scenario of more or less damage?

In order to understand coastal processes such as those outlined above, it is critical that we spend some time exploring each of these processes and get to know how storms and tsunamis are generated, and how they impact coastlines and coastal landforms. In the following sections, you will explore how and why storms occur in different coastal settings and explore briefly why storms of various origins can produce so much damage. In subsequent modules, this information will be critical to evaluating further how coastal processes impact human societies and how we might adapt to or mitigate their impacts.

×

Figure 5.8: Hurricane Katrina - Before and After - Biloxi, MS
Credit: USGS: Biloxi

×

Figure 5.9: Photograph taken in October 2009, four years after Hurricane Katrina and its storm surge impacted the shoreline at Gulf Park, Mississippi. Student climbed the tree and found trash and other debris embedded in the notch of the tree at the height of his hand. At a height of over 12' above the ground, it is hard to imagine the volume and power of the water as it eroded homes completely off their foundations (see the flat foundation slab to the left of the picture). In addition to destroying the two and three story family homes that made up this entire shoreline community, the storm surge resulted in the uplift of most of the sewage, electrical, and other infrastructure elements when the air trapped inside and under them became buoyant and lifted out of the ground. The large concrete sewage culverts in the photo are new and had yet to be installed in 2009 – one of the reasons the community had yet to rebuild.
Credit: Sean Cornell

×

Figure 5.10: Ground floor of one of the residence halls at the University of Southern Mississippi Gulf Park Campus at Long Beach. This residence hall was located on the north side of U.S. 1 and at an elevation of around 6' above mean sea level. Students undoubtedly enjoyed the opportunity to walk down to the shore and take a quick swim in the gulf; but, as Katrina hit, storm surge quickly inundated the ground floors of their residence halls. Although the buildings were able to withstand the wind and surge, many of the windows and doors were destroyed by the water. With a 12' storm surge (or even higher), even well-built brick and concrete buildings suffered significant levels of damage. Wood-framed homes like the Provost's residence didn't stand a chance and they were washed away.
Credit: Sean Cornell

×

Figure 5.11: Outside of the same residence building – showing the broken windows.
Credit: Sean Cornell