|
IIRC, Camille, in 69, had an eye that was only five miles wide. It went ashore in Pass Christian and Bay St. Louis, and barely affected anything on the other side of Biloxi Bay, 26 miles away. Katrina went ashore in the exact some location, and there was flooding as far away as Pensacola, Florida. Places like Mobile and Bayou Labatrie, AL, had extreme hurricane damage. And Katrina, in terms of wind speed and barometric pressure, was a Category 3, whereas Camille was a Cat 5, and the strongest to ever strike the mainland of the US. Katrina, though, had a larger and wider storm surge, and that is what caused the worse devestation on the Mississippi Coast. Houses that were high and dry during Camille were destroyed by Katrina.
So hurricanes vary drastically in size. Also, the rating system isn't always indicative of the damage it will cause. The worst ever was the Galveston Hurricane of 1900, and it was a Cat 3, they claim. It wiped out Galveston and killed 8,000 people. Katrina was second, and it was also a Cat 3.
As for New Orleans, Katrina glanced off it. The northwest quadrant of the hurricane is the weakest and smallest, and yet it burst levees, caused others to collapse, and flooded NOLA, then went on to devastate towns far inland with wind and constant rain. Because it was slow moving, immense, and because it made an odd turn just inland, it soaked and pounded inland regions far longer than Camille did, and caused worse damage further away from the center.
(Skip the next two paragraphs if you want, they are just detail).
New Orleans east got a Category 3 level hurricane at best from Katrina, and the it got a strong storm surge through the lakes that topped the levees along the lake. Part of the surge washed up the Mississippi River-Gulf Outlet canal (Mr. GO), and that storm topped the levees along Mr GO and flooded the Lower Ninth Ward. Mr. GO empties into the Industrial Canal, and the storm surge washed into that canal, and caused one of the levees to catastrophically fail during the early storm. This was probably the greatest cause of death, as rushing (as opposed to rising) waters flooded houses so quickly people had no time to respond, and washed houses off their foundations, etc. This was the levee some people think was blown, because it collapsed so loudly and violently. The same storm surge topped levees along Lake Pontchartrain to the north of New Orleans, and flooded a lot of regions there.
The Industrial Canal is just to the east of the main city of New Orleans (the French Quarters and downtown areas--what people think of as "the city"). The city (west of the IC) was hit by in effect a Category 2 or even 1 level storm. The wind damage was minimal for a hurricane, and this area suffered no direct storm surge. Here the rains and rising tides caused the levees along drainage canals to crumble, and caused pumps that normally lift water from the city into these canals (which flow into Lake Pontchartrain) to fail. This is what caused most of the flooding after the hurricane. Water was flowing from the canals into the Lake, but since the Lake was above normal (though not above its levees), the water could not flow into the Lake. When the levees crumbled (this is sort of in northern New Orleans) the drainage canals and the Lake itself began flowing into the city, until the water level neutralized. If you saw the footage of Senator Landreiu crying because of the meager efforts to patch a levee, this is the region she was crying over. This flooding continued to rise over several days, as water from the hurricane inland continued to drain into Pontchartrain, and then into the city.
So there were three types of flooding: topped levees (the water washed over them), broken levees (allowing water to gush or leak through), and rainwater flooding.
So the short answer is that a hurricane doesn't have to hit New Orleans directly to cause much of the devastation we saw with Katrina, because Katrina didn't hit New Orleans directly. Now, the damage we saw in Mississippi was the result of a direct hit, and was far worse initially than what New Orleans suffered. But New Orleans suffered more damage after the hurricane from failed levees and government inaction, whereas in Mississippi once the hurricane was passed, the damage ceased and they were ready to start cleaning up (not that that was easy).
Also, remember Rita, a couple weeks after Katrina. That hurricane didn't even touch New Orleans, yet it caused the newly repaired Industrial Canal levee to collapse again, just from the rain. The waters of the IC were still very high, so it did not take much to top the levee, though, so it should not collapse that easily again.
|
Printer-friendly format
Email this thread to a friend
Bookmark this thread
(1000+ posts)
Send PM |
Profile |
Ignore
