The resilience of New Orleans and other vernacular.

[pdxtex]

New Orleans amazes me. It must be an aerodynamic city. Stay with me. While the city is obviously prone to flooding, how does it survive high wind speed while coastal Florida always gets flattened? Most of the houses are single story, shot gun homes. Stick built or brick too. Crazy. Maybe all those tightly packed houses act like an airplane wing.

[JManc]

New Orleans is quite a bit inland.

[pj3000]

Originally Posted by pdxtex

New Orleans... how does it survive high wind speed while coastal Florida always gets flattened?

What are you referencing here to make this assertion?

[galleyfox]

Originally Posted by pdxtex

New Orleans amazes me. It must be an aerodynamic city. Stay with me. While the city is obviously prone to flooding, how does it survive high wind speed while coastal Florida always gets flattened?

I don’t believe New Orleans has ever had a direct strike from Category 5 winds.

Hurricane Katrina was Category 3 when it impacted New Orleans, and Category 3 winds don’t really destroy residences that are more sturdy than a mobile home.


The Florida hurricanes you’re thinking of are Category 4 and 5. In Florida, most long-time residents don’t worry about Hurricane winds below Category 4 unless they have large trees on the property.

But wind is such a low priority in a hurricane. It’s the water that usually kills you.

[Crawford]

New Orleans, due to the massive post-Katrina investments, is probably one of the more secure coastal or near-coastal U.S. cities. It will probably be around 500 years from now.

Miami, on the other hand, probably won't be around in its current format 50-70 years from now, given the unfixable groundwater/limestone issues.

[pdxtex]

Originally Posted by pj3000

What are you referencing here to make this assertion?

Hurricane Andrew, Michael and Charley were doozies but most of the damage was always low density suburban tracts. My main surprise with New Orleans is the vernacular. All those shotgun houses are over 100 years old. New Orleans has had 15 direct hit category 3 or greater storms in last 100 years. Something about the packed density must have a mitigating effect on wind damage.

[mrnyc]

i was talking to a guy just last night about new orleans. he worked there for five years around katrina and he said he was surprized how quickly they cleaned up.

[iheartthed]

Originally Posted by pdxtex

Hurricane Andrew, Michael and Charley were doozies but most of the damage was always low density suburban tracts. My main surprise with New Orleans is the vernacular. All those shotgun houses are over 100 years old. New Orleans has had 15 direct hit category 3 or greater storms in last 100 years. Something about the packed density must have a mitigating effect on wind damage.

According to this, Hurricane Zeta in 2020 was the strongest storm to ever have a direct hit on New Orleans, yet it was just a category 3. So New Orleans has probably just been lucky so far to avoid a direct hit by a storm with higher winds. But it obviously wasn't lucky to avoid a massive storm surge producing hurricane.

[galleyfox]

Originally Posted by pdxtex

Hurricane Andrew, Michael and Charley were doozies but most of the damage was always low density suburban tracts. My main surprise with New Orleans is the vernacular. All those shotgun houses are over 100 years old. New Orleans has had 15 direct hit category 3 or greater storms in last 100 years. Something about the packed density must have a mitigating effect on wind damage.

Direct Hit is being very generous.

If the eyeball doesn’t make direct impact, then the full force of the storm isn’t felt. I rode out Charley and Wilma. And my Mom went through Irma.

Just getting hit by a band doesn’t count. It’s the inner eye wall (Northeast corner) and random tornadoes that cause the wind damage.

I don’t believe New Orleans has had a direct hit from the inner eyewall in recorded history from a higher category

https://twitter.com/bhensonweather/s...YeWJmcoqUIKHxQ

[galleyfox]

I cannot even begin to describe the difference between a direct eyewall strike at Cat 2 and Cat 4. Simply incomparable.

Hurricane Charley - Cat 4 / borderline Cat 5

https://youtu.be/unV5KcSrY-I

Hurricane Zeta - Cat 2

https://youtu.be/7m6075NYY7I

[mrnyc]

^ whoa — with that history it looks like nola has just been plain lucky so far re a direct hit.

[galleyfox]

Originally Posted by mrnyc

^ whoa — with that history it looks like nola has just been plain lucky so far re a direct hit.

Exactly. Remember that it was actually the towns near Gulfport, MS that had the direct hit from Katrina. With similar housing as Louisiana.

Obliteration.

[bigstick]

Originally Posted by Crawford

New Orleans, due to the massive post-Katrina investments, is probably one of the more secure coastal or near-coastal U.S. cities. It will probably be around 500 years from now.

Miami, on the other hand, probably won't be around in its current format 50-70 years from now, given the unfixable groundwater/limestone issues.

I highly doubt it.

[pj3000]

Originally Posted by pdxtex

Hurricane Andrew, Michael and Charley were doozies but most of the damage was always low density suburban tracts. My main surprise with New Orleans is the vernacular. All those shotgun houses are over 100 years old. New Orleans has had 15 direct hit category 3 or greater storms in last 100 years. Something about the packed density must have a mitigating effect on wind damage.

So, first of all, you're comparing an entire state that's probably around 70,000 square miles with a city area that maybe encompasses 500 sq miles. Cities line the 1,300-1,400 mile coastline of Florida... so let's just talk about odds of a city in the direct path of Cat 4 or 5 powerful hurricane, get it?

If New Orleans got hit directly with 175-190 mph sustained winds, much of the "packed density" wood frame housing would likely be obliterated. Just like areas of Mississippi were in 1969 from Hurricane Camille.

[pj3000]

Originally Posted by galleyfox

Exactly. Remember that it was actually the towns near Gulfport, MS that had the direct hit from Katrina. With similar housing as Louisiana.

Obliteration.

Right, same situation/same location in 1969 with Camille.

[galleyfox]

Originally Posted by pj3000

Right, same situation/same location in 1969 with Camille.

Simply one of the most bewildering posts I’ve ever read. “Packed density” and “mitigating wind damage” are too phrases that should never be combined.

Density increases wind damage because of all the extra debris flying around.

Except for concrete structures, because concrete can withstand high winds pretty well.

New Orleans in a Category 5 should be completely evacuated because it would suffer a fate like Galveston, TX.

[pdxtex]

Originally Posted by galleyfox

I cannot even begin to describe the difference between a direct eyewall strike at Cat 2 and Cat 4. Simply incomparable.

Hurricane Charley - Cat 4 / borderline Cat 5

https://youtu.be/unV5KcSrY-I

Hurricane Zeta - Cat 2

https://youtu.be/7m6075NYY7I

Jeebus. That first video is terrifying.

[pdxtex]

Originally Posted by galleyfox

Simply one of the most bewildering posts I’ve ever read. “Packed density” and “mitigating wind damage” are too phrases that should never be combined.

Density increases wind damage because of all the extra debris flying around.

Except for concrete structures, because concrete can withstand high winds pretty well.

New Orleans in a Category 5 should be completely evacuated because it would suffer a fate like Galveston, TX.

Its just an oddball theory. All of the housing in the central neighborhoods is nearly the same height, roof pitches are similar and everything is close together. Its built like a Frisbee. They should make a scale model of it and put it in a wind tunnel. Anyway, its surprising to me half of that sh!t is still standing. I was looking at Google maps and saw some neighborhood not far away and every house was covered in blue tarps but central housing looked fine. I guess its that eyewall effect you are talking about. Zoom into Luling and St. Rose. What storm was that?

[JManc]

Guys. Look at a map. New Orleans is not Galveston or Miami. Same reason Houston is far less vulnerable to severe wind damage than Galveston. There are still places in New Orleans that never recovered from the flooding during Katrina and likely will never be.

[ardecila]

Originally Posted by Crawford

New Orleans, due to the massive post-Katrina investments, is probably one of the more secure coastal or near-coastal U.S. cities. It will probably be around 500 years from now.

That's what they said after Hurricane Betsy in the 60s. The levees they built back then failed in Katrina, after only 40 years.

New Orleans is built on thousands of feet of spongey silt that is constantly sinking due to natural and man-made factors, so levees of a certain height become less effective every year. That's before you factor in general sea-level rise, and an increase in the severity and height of hurricane storm surges due to climate change and the loss of natural barrier wetlands.

I'm not sure an engineering solution to this problem is even possible, and it would be orders of magnitude more than what the Army Corps has built post-Katrina.