Katrina’s Surge, Part 12

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 we look at the coastline of the communities of Biloxi and D’Iberville. From Google Maps, the location of this area along the Gulf of Mexico coastline impacted by Katrina:

Image courtesy of Google Maps

The only two areas touched on in Mississippi by the news media, and only briefly, were Waveland and Biloxi. Waveland gained the media’s attention because a large portion of the town, south of the railroad tracks, was completely gone, leaving only miles of slabs. Biloxi was in the news because it is the largest city on the Mississippi Gulf Coast, and because it was home to a number of large casino barges, which all floated into the city and were left sitting over slabs and in a couple of cases, right over the coastal road, Hwy 90. These large casino barges got a lot of media attention, possibly because of their size and the incongruity of seeing them in the middle of what used to be residential areas, but after all they did float, and so it wasn’t that big a surprise that they were washed ashore.

An example can be seen in the NOAA aerial below and a zoom in on the Biloxi Grand Casino:

Image courtesy of NOAA

Image courtesy of NOAA

Now here’s a Digital Globe image showing where the barge was originally, before the storm:

Image courtesy of Digital Globe

I remember at the time being fairly irritated at the focus on the barges when I wanted to see what had happened to homes. What had happened was that homes along the coast were obliterated, and in eastern Biloxi, the peninsula that lies between the Gulf and Back Bay, called Point Cadet, destruction was complete. Also hit hard was anyplace along the bay, especially, in Harrison County, the small town of D’Iberville.

West of Point Cadet, the area leveled by surge was a narrow strip along the shoreline, which included the Biloxi Coliseum, Edgewater Mall, and the historic Beauvoir. Below is tbe shoreline of central Biloxi, just to the east of those landmarks. This made it possible for the Harrison County EOC to remain intact without surge damage, unlike the Hancock and Jackson County EOCs, which were destroyed.

Image courtesy of NOAA

After the storm the beach was littered with debris, as was the rest of the coastline, in addition to the extraordinary amount of debris that was washed into the Mississippi Sound:

Image courtesy of FEMA from KatrinaDestruction

Image courtesy of KatrinaDestruction

Much of Biloxi runs along a peninsula between Biloxi Bay and the Gulf. The area of the bay behind the peninsula is known as Back Bay, as is the area of the peninsula facing it. The tip of the peninsula, east of Keesler and I-110, and south of D'Iberville, is the area of Biloxi known as Point Cadet (refer to the detailed map below).

The Point Cadet area that was obliterated by surge contained many small historic cottages. Here’s a closer look with Mapquest showing the area:

Image courtesy of Mapquest

And here’s another zoom from the previous NOAA aerial image of Point Cadet, showing the devastation we have come to be familiar with, traveling down the coastline:

Image courtesy of NOAA

And here’s another Digital Globe image showing this area before the storm:

Image courtesy of Digital Globe

This extraordinary series of photos of the Biloxi damage was taken by Brendan Holder from a site with many photos of Katrina,

PhotosFromKatrina. Note that most of the structures in the photos are historic cottages, dating from about 1875 to 1925 (Biloxi has been settled for over 300 years). The Point Cadet area also contained older historic structures that were destroyed, dating from around 1825. Most historic districts were decimated along the MS coastline.

Images courtesy of Brendan Holder

People were left with little way to identify their property and so used whatever was available:

Image courtesy of Brendan Holder

The strong sense of community and social interaction, and the never-give-up spirit of the Mississippi Gulf Coast, gave rise not only to many American flags being hung, draped, or flown from the wreckage of many homes and slabs, but to signs like these:

Image courtesy of Brendan Holder

This pbase photo album, labeled only "insurancepi," contains many, many photos of Katrina's destruction along the Mississippi coast.

Video of surge coming into Biloxi Point Cadet area: Remarkably, there exists a video of the storm surge coming into the Biloxi Point Cadet area, taken in the parking garage of the Beau Rivage Casino. It is about a 10 minute video and is extremely interesting as an observation of the behavior of the surge (it has been watched "ad naseum" at NHC and viewed extensively over the web).

The surge came in initially like a high tide, but quicker, with breakers onshore of only one to three feet. The views out the back of the garage, of the casino barge behind the large hotel, showed breakers that were considerably higher, as the surge continued to come in, but these dissipated quickly prior to reaching the shoreline. No dramatic surface current is observed. No 25-foot bulldozer of water running 100 mph, but remember the power of a three-foot wave going 15 mph, followed by a lot more water. The video shows that the current and the swells were from the SSE, and the wind was onshore. There was likely wave runup over all of Point Cadet of one to one-and-a-half feet, inland from the shore. The force of the waves as the surge spread inland, along with the current, and the strong force the standing water would have exerted on buildings, if they did not flood immediately, would have been enough, and was enough, to destroy all homes in this area, traveling a leisurely ten to fifteen mph. Remember that once the initial rise in water had occured, the bulk of the surge came quickly, which would result in what would appear to be a rapid rise of water inland of the shoreline.

The windspeed in the video matches the last wind obs from Keesler AFB before power failure, a sustained wind of 60 mph, with a peak gust of 98 mph, at 9am CDT. This also corresponds with what can be seen in the video (leaves still remaining on the trees, trees not bending over, branches remaining on trees, there is little foam being blown up off the surface of the water). The start of sustained hurricane force winds (Cat 1 intensity) would have arrived around 10:30 or 11 am, and gusts at that time would have increased to around 115 to 125 mph. This starts to occur at around 5:30 min into the video, when the surge has peaked. An example of the quick gusts that occur can be seen at 7:10 min. Note that pelicans are having no trouble riding out the storm on the surface of the water (dolphins were not so lucky).

From other reports, it is known that the water started coming over Hwy 90 between 7:30 and 8 am, and that the surge peaked around 10:30 to 11 am, before starting to recede. There is a long break in the video, timeline-wise, and then in the last minutes it can be seen that the surge is receding while winds are starting to pick up a little. The higher winds can be noted after the break, at around 8:40 min (note the garage would funnel the winds and make them faster than what was occuring outside). At 9:40 min a large breaker can be seen hitting against the outer corner of the casino barge (the wall has already been broken away by previous breakers), and dissipating almost immediately in the floating docks. At 9:50 min the surge has peaked and is starting to recede as can be seen by looking at the direction of the current (these shots are facing northeast into the Point Cadet area; note that mainly treetops are visible above the surge).

This was a surge of about 22-24 feet (the Beau Rivage sign, which can be seen in some of the images, is at about an elevation of ten feet, just next to Hwy 90).