Katrina's Surge, Part 2

A Weather Underground 16 part series about Hurricane Katrina, by Margie Kieper.

For the remainder of the month, we're traveling the coastline destroyed by Hurricane Katrina's record storm surge. This is something that has never been shown on the news or talked about, either in the overall, or in detail. What you'll be seeing here is what people on the Gulf Coast have been calling the “Invisible Coastline” for almost a year now.

Today's journey takes us along a 20-mile stretch through Pilottown, Orchard-Venice, Duvic, and Boothville. This area was almost completely destroyed by Katrina, and one year later, these communities have not been able to rebuild. The future of these communities is unclear.

Venice LA

Image courtesy of Google Maps

Comprising the southeastern portion of Louisiana and the Mississippi delta, Plaquemines Parish (Louisiana is the only state to have parishes instead of counties) has one of the most unusual geographies of any county in the US. It begins southeast of NOLA Parishes, and the southern two-thirds of it that is habitable (unless you count houseboats) consists of only a tiny strip of land running parallel to the Mississippi River, and only a few miles wide.

Map of Plaquemines Parish

Image courtesy of Plaquemines Parish

This land is only habitable because it is surrounded by levees, with one levee on the east, running along the river, and another levee on the west, bordering the bayou. However, the levees are cut between each town to allow river access, and so there are also small levees to the north and south, entirely enclosing the communities. So these levees are also known as “ring levees;” think of a shape like an elongated bathtub. And when Katrina pushed water into these ring levees, it stayed there, with no way to remove it until equipment could be brought in to pump out the water or make a cut in the levee to let it run out. Because the entire infrastructure of this area of the county was destroyed, there was no way to remove the corrosive salty water for weeks and weeks. Citrus groves, a major element of Plaquemines industry, were ruined.

There is only one road connecting all of these communities, running to the west of the river, local route 23, and this road ends at Venice, which also includes the community of Orchard.

Venice and Orchard LA

Image courtesy of Google Maps

This has earned Venice the nickname, “The end of the road.” However, there is another very small community about ten miles southeast of Venice, that is only accessible by boat or helicopter, and that is Pilottown, so called because its own residents, part-time ones, are river boat pilots who guide boats along the Mississippi River.

Katrina hit lower Plaquemines head-on

This entire area received the full force of the winds from Katrina's large eyewall. The official landfall location was Buras, LA, which is the point where the geographical center of the eye crosses land. But Katrina's eye was so large that by this point in time, the powerful eyewall winds had already passed over the entire lower two-thirds of Plaquemines:

Radar of Katrina Landfall

Image courtesy of Mobile NWS; for the entire animated radar image, link here (SWF File)

It is hard to imagine exactly what this experience would have been like to observe. This area is surrounded by marsh, which would have all been underwater hours prior to the arrival of the eye. As weather worsened, the ring levees would have been surrounded by a sea of water topped with significant waves, with no other land anywhere in sight. With the final rush of the surge, in which water rises very quickly, just prior to the arrival of the eyewall, water would have spilled over the levees and filled the communities, and at that point, no land anywhere would have been above water, just the higher floors of some buildings and oil refineries. This location in effect became, temporarily, part of the Gulf of Mexico. The waves and strong current within the ring levees, driven by the winds, ripped apart most of the residential structures, both frame houses and the many mobile homes. This wreckage was pushed around by the current while the hurricane moved north over the area.

After the eyewall passed, and the surge receded (which would have occurred surprisingly quickly), the ring levees remained filled with water. This made access by road impossible, and in many places boats remained washed onto the road, even a freighter sitting on the road running on top of a levee!

Most trees were blown down by the winds (note: it does not take much wind for blowdown to occur and can occur at Cat 1 intensity; massive blowdowns in Minnesota over the years from derechos have occurred with winds between 60mph and 100mph). In tomorrow's aerial images, you will see trees consistently blown down towards the northwest. This is due to the initial strong winds from the northeast eyewall (which had winds curving around from the southwest).

Understanding the scale of the destruction

It is worthwhile to provide a perspective for understanding the scope of the destruction that you are about to see from the NOAA aerial images.

After every hurricane, NOAA immediately takes aerial images of the destruction that occurred, and this begins starting the next day, and continues for as many days as required, as weather permits. NOAA took more images for hurricane Katrina than any other hurricane, by several magnitudes. And while media focused almost exclusively on New Orleans, LA (NOLA), note that in the scope of the damage documented by NOAA, NOLA is only a very small portion of the area affected by the storm. And the majority of the areas affected were, unlike NOLA, coastal areas that were inundated and destroyed by surge higher than any other hurricane in recorded history. In fact, this disaster was the largest disaster in terms of coastline affected, in the entire history of our country; an area of coastline equivalent to the distance from New York City to Washington, D.C. was completely destroyed, an area that included on the order of 100 communities and cities.

How this never made a headline is a mystery to everyone on that coast.

This map shows the areas damaged by the hurricane where NOAA obtained aerial images of damage. Each major section is identified by a block:

NOAA Katrina Images Base Map

Image courtesy of NOAA -- link

Now if you drill down to one of the boxes, you see the many images available to view for that location:

NOAA Katrina Images Lower Plaquemines

Image courtesy of NOAA -- link

And if you select on any one of these images -- and let's select the lower end of the ring levee surrounding Venice, which is completely flooded -- this is what you will see:

NOAA Katrina Images Venice

Image courtesy of NOAA -- link

Note: While reading this entry, you can interactively link to any of these images, to see more detail than is provided here, by linking (in a new window), cursor over the image, and then select the box that appears in the lower RH corner to zoom in on the image.

At that height, in the previous image, you can see the Mississippi River to the east (the top of this image is facing south, so that is on the left side of the image), marsh to the west of the ring levee (on the right side of the image), and the entire ring levee area is still inundated with water now that the hurricane has passed -- but you cannot really see any of the damage, except to observe ships stranded against the levee and overturned in the marsh. You can also see the massive debris floating on the top of the water as a brown ring around the edges of the flooded area. If you zoom in on a very small part of this image, then more detail is available:

NOAA Katrina Images Venice - Detail

Image courtesy of NOAA

The water has reached almost to the tops of the trees of a citrus grove, and buildings are flooded to the rooftops, while boats and debris are left washed against the levee, after the receding surge in the marsh.

Everywhere in the community, homes are flooded to the roofs, with debris floating in the water and scattered on the banks of the levee:

NOAA Katrina Images Venice - Detail 2

Image courtesy of NOAA

Multiply the size of one house in the size of the original image; multiply the original aerial image by 100s, then you can begin to wrap your mind around the scope of devastation along this stretch of lower Plaquemines Parish.

Images of damage to the Venice - Duvic - Boothville area

Following are some more aerial images of the damage along the 10-mile stretch of land between Venice and Boothville.

Below is an image of what remained from another community here, Duvic. What is striking about this image, taken just six days after the storm, on September 4th, is not only that boats can be seen on the river, but that the sun shining on the water highlights the completely-inundated ring-levee and community within, making it appear to be a second river:

NOAA Katrina Images Duvic

Image courtesy of NOAA -- link

The following image show a very narrow section of the ring levee north of Duvic, again facing south, with the river to the east of the community and the marsh to the west, still flooded.

NOAA Katrina Images north of Duvic

Image courtesy of NOAA -- link

A detail from the image shows this area to be completely trashed, with massive debris floating on top of the water, and it can be observed that wind damage has blown the roof off of many of the remaining flooded structures:

NOAA Katrina Images Duvic - Detail

Image courtesy of NOAA

Here are links to additonal aerial images of that area: a more complete image of Venice, the area south of Boothville, and Boothville (this image facing north), all numbingly the same -- miles of communities swallowed by water, and pounded by wind and the strong force of the current as the surge poured into the ring levees. Incredibly, it would be to too repetitious to show all the images and their details here! This entire area of the country was completely destroyed.

Here is detail from the northern section of the area covered today, just north of Boothville, with the river along the east, sun shining on the flooded levee area, and flooded buildings surrounded by debris floating on top of the water:

NOAA Katrina Images north of Boothville - Detail

Image courtesy of NOAA

If you link to the south of Boothville image, you'll see a large building. This is the Boothville High School, which can also be seen here:

Boothville High School

Image courtesy of Plaquemines Parish Government

Here is a photo of the Fort Jackson football field stadium (only the very top of the stadium seating is above the top of the water):

Fort Jackson stadium

Image courtesy of Plaquemines Parish Government

This boat is actually moving right on top of what was Hwy 23 in Boothville. Remember the water never went down in this area, trapped by the ring levees, until the levees could be cut and the water drained out into the marshland.

Boating along Hwy 23

Image courtesy of Plaquemines Parish Government

Here are a couple more images of the flooding in Plaquemines Parish (there is also a town called Plaquemine, south of Baton Rouge!):

Plaquemines flooding

Image courtesy of Plaquemines Parish Government

Plaquemines flooding 2

Image courtesy of Plaquemines Parish Government

Note: Each day, along with the coastal images, meteorological information about Katrina will be provided. Tomorrow: How is surge formed in hurricanes? Why do only some hurricanes hit landfall with a damaging storm surge?

Hurricane Katrina Storm Surge:

Weather Underground Storm Surge Articles

Storm Surge Safety Actions

  • Minimize the distance you must travel to reach a safe location; the further you drive the higher the likelihood of encountering traffic congestion and other problems on the roadways.

  • Select the nearest possible evacuation destination, preferably within your local area, and map out your route. Do not get on the road without a planned route, or a place to go.

  • Choose the home of the closest friend or relative outside a designated evacuation zone and discuss your plan with them before hurricane season.

  • You may also choose a hotel/motel outside of the vulnerable area.

  • If neither of these options is available, consider the closest possible public shelter, preferably within your local area.

  • Use the evacuation routes designated by authorities and, if possible, become familiar with your route by driving it before an evacuation order is issued.

  • Contact your local emergency management office to register or get information regarding anyone in your household whom may require special assistance in order to evacuate.

  • Prepare a separate pet plan, most public shelters do not accept pets.

  • Prepare your home prior to leaving by boarding up doors and windows, securing or moving indoors all yard objects, and turning off all utilities.

  • Before leaving, fill your car with gas and withdraw extra money from the ATM.

  • Take all prescription medicines and special medical items, such as glasses and diapers.

  • If your family evacuation plan includes an RV, boat or trailer, leave early. Do not wait until the evacuation order or exodus is well underway to start your trip.

  • If you live in an evacuation zone and are ordered to evacuate by state or local officials, do so as quickly as possible. Do not wait or delay your departure, to do so will only increase your chances of being stuck in traffic, or even worse, not being able to get out at all.

  • Expect traffic congestion and delays during evacuations. Expect and plan for significantly longer travel times than normal to reach your family's intended destination.

  • Stay tuned to a local radio or television station and listen carefully for any advisories or specific instructions from local officials. Monitor your NOAA Weather Radio.

Source: NOAA

Hurricane Preparedness

National Hurricane Center

Centers for Disease Control & Prevention