What if Katrina had hit New Orleans?

[LSU]

Someone asked this in another post. The eye went about 20-30 miles east of downtown. What if the eye of Katrina went directly over NOLA or slightly to the west?

What would the wind damage have been?

How much higher would the storm surge have been?

How many more levees would have broken?

[Anonymous]

Hiroshima...

Either way, New Orleans got screwed. That eye was too big, and the surge was too high...it got too close.

[superfly]

Winds higher, surge lower.

[superfly]

The only levee that would have broke would have been the Industrial canal which collapsed during the actual storm. The westerly winds in the southern part of the storm would have pushed water back out of the Lake into the Gulf had it been a direct hit or to the west of New Orleans. Wind damage would have been a lot higher, but from the angle Katrina approached New Orleans, the path it took was the worst case scenario as far as surge goes.

[Derek Ortt]

surge would have came from the GOM, not the Lake, meaning the flooding would have been from a different direction and the city may have been more vulnerable since the protection from the GOM isnt quite the same

[superfly]

surge would have came from the GOM, not the Lake, meaning the flooding would have been from a different direction and the city may have been more vulnerable since the protection from the GOM isnt quite the same

The city is not on the shore. There is quite a bit of land buffer from surge coming from the Gulf.

[LAwxrgal]

Hiroshima...

Either way, New Orleans got screwed. That eye was too big, and the surge was too high...it got too close.

I agree. Someone mentioned to me that the wind damage would have been greater than it was. Either way, NOLA itself saw Cat 2 max winds, and the western eyewall passed over NOLA east and the Lower 9th ward, the hardest hit area of the city. NOLA and the rest of the N GOM area was pretty much doomed either way as soon as Katrina started moving SW in the GOM. You just knew that the other shoe was going to drop and she was going to have to turn north at some point. Even if she had hit, say, Mobile (which is a little further east of where she actually made landfall) New Orleans would still have felt a big impact because this storm was so large and powerful.

Also, I think the water would have risen faster in the city, and instead of myriad rooftop rescues being performed, they would have found bodies there instead.

It was still pretty bad though. The only thing that saved this area from worse effects was the dry air infiltrating the west side of the storm.

Superfly: While it's true that NOLA isn't exactly on the shore, there isn't as much land buffering New Orleans as there used to be due to erosion.

[Brent]

The Superdome probably would have faired far worse, and possibly even collapsed killing the people inside. More skyscrapers would have had windows blown out too.

[Derek Ortt]

the surge would have came right through the marshland, much of which has eroded away and is open ocean or lake-like

They would have had about 15 feet in the city had it hit to the west. They had about 5 from Betsy in 1965, which passed well to the west

[curtadams]

the surge would have came right through the marshland, much of which has eroded away and is open ocean or lake-like

They would have had about 15 feet in the city had it hit to the west. They had about 5 from Betsy in 1965, which passed well to the west

The Mississippi River lies to the south of New Orleans proper. Those levees are enormous because the river's normal height is over 10 feet about ground. Even a Cat 5 surge wouldn't breach those, not with 30+ miles of marsh to the south. I don't think the river levees breached even in Plaquemines. The suburbs of NO to the south would have been clobbered from a direct hit but the city would probably have been better off. The wind damage would have been much worse but the levees would have been under far less strain.

[skysummit]

the surge would have came right through the marshland, much of which has eroded away and is open ocean or lake-like

They would have had about 15 feet in the city had it hit to the west. They had about 5 from Betsy in 1965, which passed well to the west

The Mississippi River lies to the south of New Orleans proper. Those levees are enormous because the river's normal height is over 10 feet about ground. Even a Cat 5 surge wouldn't breach those, not with 30+ miles of marsh to the south. I don't think the river levees breached even in Plaquemines. The suburbs of NO to the south would have been clobbered from a direct hit but the city would probably have been better off. The wind damage would have been much worse but the levees would have been under far less strain.

How can you even think about saying that? With Katrina, New Orleans was flooded from lake waters that flow through the 17th street canal and numerous other canals. If a storm would go just to the west of New Orleans, not only would the Lake continue to fill up and overtop or breach those same levees, but all the marshes to the south would be filled, and water would constantly be pushed up the Miss. River...eventually overtopping those levees. Water would not only come in from the Lake, but it would come in from all directions. Not to mention the Westbank would get completely flooded also.

[JTD]

The Superdome probably would have faired far worse, and possibly even collapsed killing the people inside. More skyscrapers would have had windows blown out too.

Absolutely. The superdome almost had it's roof blown off from the force of the winds they did get. If a 145 mph storm had hit head on, the 35,000 people in the superdome would have been killed in the collapse undoubtedly We'd be hearing about the odd miraculous survival story.

Also, downtown New Orleans would look like Gulf Port, MS or perhaps even worse. It'd be completely gone. In fact, the NWS expert who wrote that doomsday warning the day the storm hit said that he expected a cat 4/5 direct hit to make New Orleans part of Lake Ponchitrain and be completely gone.

[patsmsg]

<cut here for brevity>...make New Orleans part of Lake Ponchitrain and be completely gone.

That is exactly what would happen. We would never even be talking about reclaiming the city ever again.

[facemane]

The Superdome probably would have faired far worse, and possibly even collapsed killing the people inside. More skyscrapers would have had windows blown out too.

I can't remember his name, but an engineer interviewed on CNN a few
days after the storm stated the Superdome could have withstood much
higher winds. It is structurally very sound. The part you saw damaged
was just a protective fabric covering. The supports were not damaged
at all.

[inotherwords]

The Superdome probably would have faired far worse, and possibly even collapsed killing the people inside. More skyscrapers would have had windows blown out too.

I can't remember his name, but an engineer interviewed on CNN a few
days after the storm stated the Superdome could have withstood much
higher winds. It is structurally very sound. The part you saw damaged
was just a protective fabric covering. The supports were not damaged
at all.

There was an engineer who posted on the pro met board pre-Katrina whose company had done an analysis of the Superdome's stormworthiness just a few years ago, and found just the opposite. He said it was a deathtrap and that all it would serve to do is to make sure all the dead bodies were in the same place for easy bulldozing afterward. His words, not mine. His report was grim. We were all fearing at that point a direct hit, and thank god the city was spared.

The CNN engineer might have been referring to the fact that the superdome was originally constructed to withstand 200 mph winds. But I wonder if he knew about this more recent engineering study.

[LSU]

Someone from the Westbank on the NOLA boards said that he was on the MS River levee right after Katrina pushed through. He also said that the river water was within a foot of overtopping the levee there, which is incredible considering that the River before the storm was close to an all-time low level.

The Jeff Parish OEP head said before the storm that a direct hit would have resulted in 40-50,000 dead in Jeff Parish alone. At first I thought it was a bit of an exaggeration, but am not sure so anymore.

Also, I don't think the city would have looked like the MS coast b/c most of that destruction, that of the absolute, wipe the slate clean kind, was caused by the storm surge. NOLA would have flooded, certainly, but the force of the waters as a result of our geography and levees I don't think could have been as strong as those of on the MS coast, except perhaps where the levees were breached (assuming the entire levee didn't completely fall apart.

As for the Superdome, I heard it was graded to 200 sustained. Looking at the structure post-Katrina, it looks like that was accurate. It might not have held completely together with 200 sustained, but it did a fine job with 110-120.

[superfly]

How can you even think about saying that? With Katrina, New Orleans was flooded from lake waters that flow through the 17th street canal and numerous other canals. If a storm would go just to the west of New Orleans, not only would the Lake continue to fill up and overtop or breach those same levees, but all the marshes to the south would be filled, and water would constantly be pushed up the Miss. River...eventually overtopping those levees. Water would not only come in from the Lake, but it would come in from all directions. Not to mention the Westbank would get completely flooded also.

You don't know the geography of New Orleans, do you? New Orleans lies to the south of the lake. A hurricane hit to the west would have pushed the lake water into NORTHSHORE as it passed by then EAST into the Gulf with westerly winds as the eye passes New Orleans. At no time would a storm passing to the west of New Orleans push surge toward New Orleans from the lake. Surge-wise, the path Katrina took was the worst case. Wind-wise, New Orleans would have suffered a far worse fate if it passed to the west but NOT surge-wise.

Granted, surge up the Mississippi River may have overtopped the levees on the river side, but as far as the lake side surge is concerned, it wouldn't have been near as bad.

[Brent]

The Superdome probably would have faired far worse, and possibly even collapsed killing the people inside. More skyscrapers would have had windows blown out too.

I can't remember his name, but an engineer interviewed on CNN a few
days after the storm stated the Superdome could have withstood much
higher winds. It is structurally very sound. The part you saw damaged
was just a protective fabric covering. The supports were not damaged
at all.

But the problem is, during Katrina, they only had Cat 2 winds at best... and mostly in gusts. I guarantee if Katrina had hit head on as a 4 or 5, things would have been MUCH worse. There would have been no survivors to feed. I thought it was a deathtrap when they first told people to go there. Fortunately, the worst of the storm missed or the fear would have been realized.

[flhurricaneguy]

i cant believe there is a what if thread

[skysummit]

How can you even think about saying that? With Katrina, New Orleans was flooded from lake waters that flow through the 17th street canal and numerous other canals. If a storm would go just to the west of New Orleans, not only would the Lake continue to fill up and overtop or breach those same levees, but all the marshes to the south would be filled, and water would constantly be pushed up the Miss. River...eventually overtopping those levees. Water would not only come in from the Lake, but it would come in from all directions. Not to mention the Westbank would get completely flooded also.

You don't know the geography of New Orleans, do you? New Orleans lies to the south of the lake. A hurricane hit to the west would have pushed the lake water into NORTHSHORE as it passed by then EAST into the Gulf with westerly winds as the eye passes New Orleans. At no time would a storm passing to the west of New Orleans push surge toward New Orleans from the lake. Surge-wise, the path Katrina took was the worst case. Wind-wise, New Orleans would have suffered a far worse fate if it passed to the west but NOT surge-wise.

Granted, surge up the Mississippi River may have overtopped the levees on the river side, but as far as the lake side surge is concerned, it wouldn't have been near as bad.

Superfly, maybe you should look into studies before telling me what I know and what I don't know. I have lived here all my life and have worked in New Orleans all my life. I know more about that city than many. Yes, a western storm would push water onto the northshore, however, the entire lake would rise. The current would be going to the northshore, but again, the entire lake would rise. Oh, and this was NOT the worst case scenario...by far. Yes, it was bad, but not the worst. There was already a HUGE thread on this so I don't feel like starting another. Before you decide what you think would happen if a storm hit just to the west of New Orleans, do a little research, and you'll see what I'm talking about.