If it had stayed a Category 5...

[Andy Wehrle]

...No news would be coming out of New Orleans and Biloxi right now because nobody would be able to find the cities under all the water. I think the scariest thing about all this is knowing that it could have been worse. :shock:

 

[Kevin Bowman]

well the worst case scenario pretty much occured with all the flooding

howver what would really be horrible is if another tropical system made landfall there. It isint even the peak of the season yet and thats pretty damn scary

 

[Jeff Snyder]

Yeah, we're having a hard to imaging the damage that there is right now. Yes, NO is flooding in many places, but I do think it could have been much worse. I don't htink it could have been much worse for the coastal Mississippi areas, but NO could have seen waters up 20' throughout the entire city, instead of in scattered spots (as is now the case, though I understand that the mayor expects the entire city to be flooded to 3' above sea level by morning). The storm surge was absolutely massive, and that was after the storm pressure rose nearly 20mb. We've seen what the 145mph winds did to coastal MS, so place that wind damage into NO, and bring coast MS winds to 175. I can't even imagine how bad it is now, and I can't even grasp how big it could have been. Not that it really matters, given the massive destruction already.

I just wonder how the Superdome would have held up. Being 20-30 miles from the eye, and on the western side yielding off-shore winds, I imagine that most of downtown NO experience 100-110mph gusts. The lining of the roof was essentially removed in most areas, and the actual roof had a few patches removed (2 areas near the size of 5'x3' from what I've heard). Now, bring gusts up to 200mph, and I can't imagine that the roof covering would not have been removed (perhaps not the supports).

Again, this is rather trivial since the damage already is catastrophic.

 

[Joe Nield]

well the worst case scenario pretty much occured with all the flooding

howver what would really be horrible is if another tropical system made landfall there. It isint even the peak of the season yet and thats pretty damn scary

That's what scares the hell out of me and all other meteorologists. You're right, we haven't even reached the climatological peak yet. This could easily happen again in a matter of weeks.

The slight weakening and slight turn is the only thing that saved the Superdome. I fully believe that. That was the only thing between the devastation now and already having a confirmed death toll in the thousands. I don't think the structure would have held up to category 5 conditions.

 

[Aaron Kennedy]

Puts a good handle on this country... we need to be able to take care of our people first before worrying about other countries.

Aaron

 

[Justin Turcotte]

Katrina appeared to really ramp up on the IR just before landfall in MS. This may have led to a lot more devastation reported well inland. A structurally weakening Cat 5 may not have lasted through Jackson, MS. Just a hunch though.

 

[Bill Tabor]

Katrina appeared to really ramp up on the IR just before landfall in MS. This may have led to a lot more devastation reported well inland. A structurally weakening Cat 5 may not have lasted through Jackson, MS. Just a hunch though.

It was a weakening Cat 5 previously surface winds of 175mph and flight level of 184 along with very low pressure. It was also a very wide extensive storm. I've heard commentary of things that survived Camille (supposedly 190mph storm) got leveled in Katrina. I wonder if somehow this immense high powered storm even though it was weakening from Cat 5 to Cat 4 really just "dumped" everything which caused more catastrophic damage similar to the way a large supercell updraft can die and cause huge microbursts. Any thoughts or opinions? Also seems I remember hearing that the damage factor between categories is almost a square of each other so the damage potential of a cat 5 would be a cat 4 (squared). Perhaps I am thinking of F ratings or inverse square law - LOL.

Also Cat 5 has no upper end. Perhaps there should be a Cat 6? :wink:

And to answer the question...I think there would have been a huge difference in 175mph winds and direct hit on NO than 145 and passing to the east. I think pretty much everything would have been leveled and shredded around NO, and then the bowl would have been up to 30 feet deep. Either way as you see the whole area still got screwed...so perhaps that analogy they were using Monday of comparing F5 to F4 as the difference between you getting hit by a freight train versus a Mac truck is reasonable.

 

[Jeff Snyder]

In my experience, I'd say that weakening storms actually tend to produce less-than-expected damage relative to strengthening storms. I mean, there were serious questions raised last year with the landfall of Ivan, and earlier this year with Dennis, in that it seemed as though the damage was considerably less intense/widespread than expected. On the other hand, take the strengthening Charlie, where damage was very intense (though localized, as it was a relatively small/compact storm). It was evident that Katrina weakened up to landfall (a look at IR shows this nicely), but I also noticed the convective burst and rapidly cooling cloud tops right AT landfall that Justin noted above. I do think this may have contributed to the intense damage in coastal Mississippi, as there was some very intense convection in the northeastern eyewall during this time. This may also explain how the eye persisted so far inland. It seemed, IMO, to sustain itself upon landfal considerably longer than many other storms. Can't confirm this, just my own opinion/observation.

 

[Mike Umscheid]

Storm Surge. Storm surge, storm surge. The slight weakening/strengthening the moments before second landfall is trivial in my opinion. This was a sub-910mb storm with 150+mph winds for quite awhile. This is incredible wind energy that was transferred to the water below. This energy will not dissipate *nearly* as much as we see weakening in flight-level winds and dropsonde pressure measurements. This is hugely important. It was a 165-175mph hurricane fairly close to the coast, and this energy transferred to the ocean doesn't simply "go away". Much like how tsunamis work... or heat capacity properties of water. Takes much longer to heat/cool water than ground. It's all about *energy*.

So you can't just automatically say "Cat 4 now, welp, storm surge will be less in the 12-15 foot range" or whatever. No way.

Mike U

 

[Rob_Davis]

Puts a good handle on this country... we need to be able to take care of our people first before worrying about other countries.

I wonder if they could pass an emergency order cancelling foreign aid for the next five years. I could go for that.

 

[Miriam Lawrence]

This doesn't directly address the strength issue, but the conclusions may be similiar.

"[Louisiana State University Hurricane Center researcher Ivor van Heerden] said that if there's a silver lining to this disastrous event, it's that the eye of Katrina didn't go directly over or to the west of the city. If that had happened, the storm surge could have been much higher and would have directly topped levees all along the lake and much more rapidly filled the bowl, which would have meant an even higher death toll than is anticipated from this slow-moving event, he said."

http://www.nola.com/hurricane/t-p/katrina....odgetworse.html

 

[Joe Zemek]

Puts a good handle on this country... we need to be able to take care of our people first before worrying about other countries.

I wonder if they could pass an emergency order cancelling foreign aid for the next five years. I could go for that.

Dude, what foreign aid? We give a smaller percentage than any country capable of giving in the first place. I think Aaron's talking about the war costs, which are exponentially more than our foreign aid.