...almost exactly 3 years after Katrina...
... there's a new potential threat. Most of the models have Hurricane Gustav headed for the center of the Gulf of Mexico, as a borderline Cat4/5 and some even have it headed straight for New Orleans, of all places... large areas of which are still a total shambles after 3 years. 
Hurricanes, once trapped in the GOM at this time of year have to make landfall somewhere, and because of the tendency for a generally northward track, the southern US coastline is most at risk. Storms can become severe, even Category 5 given optimum conditions (but very rarely at landfall), as we saw in 2005 with the "Fearsome Fivesome" of Dennis, Emily, Katrina, Rita and Wilma (a cat 4 and four cat 5s).
What may happen with Gustav? Will this become a huge news story within a week, with yet another major disaster on our hands with deaths and injuries and massive coastal damage from the storm surge, wind and rain, and all the standard accompanying ineptitude from the department of Homeland "Security" and FEMA, plus the use of paramilitary thugs from Blackwater etc. to further terrorize the folks whose homes and livelihoods have been erased? Or will Gustav fail to materialize as a major storm due to (land interaction, shear, dry air entering the circulation, etc etc) and become a footnote in the NOAA archives?
In amongst the ranks of armchair generals here... do we have any armchair meteorologists? What's going to happen with this one? (Hopefully nothing). Thoughts?
Hurricanes, once trapped in the GOM at this time of year have to make landfall somewhere, and because of the tendency for a generally northward track, the southern US coastline is most at risk. Storms can become severe, even Category 5 given optimum conditions (but very rarely at landfall), as we saw in 2005 with the "Fearsome Fivesome" of Dennis, Emily, Katrina, Rita and Wilma (a cat 4 and four cat 5s).
What may happen with Gustav? Will this become a huge news story within a week, with yet another major disaster on our hands with deaths and injuries and massive coastal damage from the storm surge, wind and rain, and all the standard accompanying ineptitude from the department of Homeland "Security" and FEMA, plus the use of paramilitary thugs from Blackwater etc. to further terrorize the folks whose homes and livelihoods have been erased? Or will Gustav fail to materialize as a major storm due to (land interaction, shear, dry air entering the circulation, etc etc) and become a footnote in the NOAA archives?
In amongst the ranks of armchair generals here... do we have any armchair meteorologists? What's going to happen with this one? (Hopefully nothing). Thoughts?
Comments
But GOM SST maps can be found from the last week of August 2005 and compared to the current GOM SST.
I did this all last season, it was like night and day, 2007 was a dud GOM SST-wise relative to the 2005 GOM SST season.
Since my Mac died I've lost all my links.
But GOM SST maps can be found from the last week of August 2005 and compared to the current GOM SST.
I did this all last season, it was like night and day, 2007 was a dud GOM SST-wise relative to the 2005 GOM SST season.
I recall there was also larger than usual amounts of dust from the Sahara carried by upper winds out over the tropical Atlantic in both the 2006 and 2007 hurricane seasons, which (from what the experts say) is not conducive to the formation of tropical cyclones.
2008 SSTs
SST in the GOM in the forecast track of Hurricane Gustav (most models are taking it over Western Cuba and then NW across the central GOM) are in the range 30-33ºC (86-91ºF), which is plenty warm enough for rapid intensification, given that the other conditions are favorable.
2005 was a weird season... a couple of hurricanes late that season formed over cool water (barely 70F!) in the central Atlantic... one (Epsilon) hung out for a week under conditions that according to the conventional wisdom would have strangled a hurricane of its energy supply in short order... the remnants of another (Vince) made landfall in Spain(!)... and the last storm of the 2005 season dissipated in early January 2006(!!).. all of which got the NOAA forecasters rethinking the how and why tropical cyclones form and sustain themselves.
I recall there was also larger than usual amounts of dust from the Sahara carried by upper winds out over the tropical Atlantic in both the 2006 and 2007 hurricane seasons, which (from what the experts say) is not conducive to the formation of tropical cyclones.
2008 SSTs
SST in the GOM in the forecast track of Hurricane Gustav (most models are taking it over Western Cuba and then NW across the central GOM) are in the range 30-33ºC (86-91ºF), which is plenty warm enough for rapid intensification, given that the other conditions are favorable.
2005 was a weird season... a couple of hurricanes late that season formed over cool water (barely 70F!) in the central Atlantic... one (Epsilon) hung out for a week under conditions that according to the conventional wisdom would have strangled a hurricane of its energy supply in short order... the remnants of another (Vince) made landfall in Spain(!)... and the last storm of the 2005 season dissipated in early January 2006(!!).. all of which got the NOAA forecasters rethinking the how and why tropical cyclones form and sustain themselves.
Yes, I saw that link.
I think over time they'll get a better handle on the ENSO, NAO, PDO, etceteras at decadal scales. But high SST and low upper atmospheric shear are what really get these things going, I'm not a SME on this mind you, but that is my basic layperson understanding.
I hope it doesn't hit NO.
And I don't want to name drop, but I know most of the USACE research scientists and engineers who were involved in the redesign of the NO levee system.
I'll have to drop in on them in the next 2-3 days, to see if all the proposed design changes have been completed. I'd say more, if I knew more, but I wasn't involved in that study at all.
And if it does like Katrina did track wise, I'm getting out of Vicksburg, because Katrina tore it up pretty bad up to 250 miles inland.
Yes, I saw that link.
I think over time they'll get a better handle on the ENSO, NAO, PDO, etceteras at decadal scales. But high SST and low upper atmospheric shear are what really get these things going, I'm not a SME on this mind you, but that is my basic layperson understanding.
I'm a total layperson on this; I have a basic understanding of the atmosphere and how it works, but I guess a lot of us do. Here's the link to the computer models' track and intensity forecasts I've been looking at. You've probably already got it perhaps?
I hope it doesn't hit NO.
omg, you can say that again. If this one took a track slightly west of N.O., at this evening's forecast intensity of 110 kt sustained winds, N.O. would catch the bullet she missed during Katrina.
Shortly after Katrina I was looking at tidal and other data which showed that the storm surge in Lake Ponchartrain was pretty much a non-event.. this bears out with the wind records in the metropolitan N.O area during Katrina.... cat. 1 hurricane force winds were only occurring locally, and for short periods... mostly at higher elevations (high rise buildings caught some really rough weather), but the sustained winds at sealevel were for the most part strong tropical storm force. The city was in the "weak" sector of the storm (40+ miles west of the western eye-wall), thus the winds backed from north east, to the north, to northwest, and then to the west as the storm tracked northwards well to the east.. and were pushing the water back out into the GOM, as opposed to what happened east of the eye... which was a huge storm surge that went inland for miles. Despite the relative lack of storm surge in N.O., the levees failed, in multiple places. Horrendous as it was, it *could* have been far, far worse... if Katrina had tracked a little west of N.O. and hadn't weakened considerably in the hours prior to landfall (from cat 5 to cat 3)... it would have been a catastrophe with many thousands more fatalities than the approx. 1850 who died that day.
And I don't want to name drop, but I know most of the USACE research scientists and engineers who were involved in the redesign of the NO levee system.
I'll have to drop in on them in the next 2-3 days, to see if all the proposed design changes have been completed. I'd say more, if I knew more, but I wasn't involved in that study at all.
And if it does like Katrina did track wise, I'm getting out of Vicksburg, because Katrina tore it up pretty bad up to 250 miles inland.
I don't blame you. I would. A really close friend of mine flew to N.O. the day after the storm hit to volunteer in rescuing hundreds of horses in the area. What she witnessed was so much worse than what we saw on television. She took her own videocamera and shot many hours of material... utterly horrific... I can't even begin to describe it.
I hope this thread is short, and Gustav falls apart somewhere where no harm can be done.
But....
I'm a total layperson on this; I have a basic understanding of the atmosphere and how it works, but I guess a lot of us do. Here's the link to the computer models' track and intensity forecasts I've been looking at. You've probably already got it perhaps?
omg, you can say that again. If this one took a track slightly west of N.O., at this evening's forecast intensity of 110 kt sustained winds, N.O. would catch the bullet she missed during Katrina.
Shortly after Katrina I was looking at tidal and other data which showed that the storm surge in Lake Ponchartrain was pretty much a non-event.. this bears out with the wind records in the metropolitan N.O area during Katrina.... cat. 1 hurricane force winds were only occurring locally, and for short periods... mostly at higher elevations (high rise buildings caught some really rough weather), but the sustained winds at sealevel were for the most part strong tropical storm force. The city was in the "weak" sector of the storm (40+ miles west of the western eye-wall), thus the winds backed from north east, to the north, to northwest, and then to the west as the storm tracked northwards well to the east.. and were pushing the water back out into the GOM, as opposed to what happened east of the eye... which was a huge storm surge that went inland for miles. Despite the relative lack of storm surge in N.O., the levees failed, in multiple places. Horrendous as it was, it *could* have been far, far worse... if Katrina had tracked a little west of N.O. and hadn't weakened considerably in the hours prior to landfall (from cat 5 to cat 3)... it would have been a catastrophe with many thousands more fatalities than the approx. 1850 who died that day.
I don't blame you. I would. A really close friend of mine flew to N.O. the day after the storm hit to volunteer in rescuing hundreds of horses in the area. What she witnessed was so much worse than what we saw on television. She took her own videocamera and shot many hours of material... utterly horrific... I can't even begin to describe it.
I hope this thread is short, and Gustav falls apart somewhere where no harm can be done.
But....
Please don't quote me on this, since it's been a while, and I may not have all the facts stated accurately.
The original design storm was a CAT3 for the levees, meaning basically a water level or a storm surge representative of a CAT3 storm.
Now I think there was agreement that the levees failed at a storm surge below the CAT3 storm event.
How do we know that?
We know that because technically an over topped levee in not a failed levee, since it withstood the design water level, was over topped but not breached.
In 2005 no levee structure was over topped (if I recall correctly), but several were breached, at water levels below the levee crest elevation (or superstructure or crown elevation).
Thus the levee system failed at several locations below the design water level, in other words below their respective maximum crown elevations.
Now, from my limited understanding of the current design, the USACE was to restore the entire levee system to at least it's prior design crown elevations. Some sections have undoubtedly been strengthened, while others that have subsided over time due to subsoil consolidation have been raised to at least their prior design elevations.
So technically it is not strictly the "CAT3" type criteria, but whether the levees withstand water levels up to and above their maximum crown elevations. And if water levels exceed the crown elevation, a properly designed levee will not be breached, but will act like a broad crested weir.
Now with respect to over topped levees, the NO situation was to have new pumping stations capable of handling
Dated 08-24-2008, doesn't make the USACE look too good.
Note: I've never been a coastal sand engineer and don't believe we should be building things at public expense in the coastal floodplains.
I've held that position ever since I started working for the USACE. I'm not a flatlander.
Even if I designed/built the entire NO levee system myself, I'd be the first one to get out of Dodge, should anything really serious show up on the radar/horizon.
Please don't quote me on this, since it's been a while, and I may not have all the facts stated accurately.
The original design storm was a CAT3 for the levees, meaning basically a water level or a storm surge representative of a CAT3 storm.
Now I think there was agreement that the levees failed at a storm surge below the CAT3 storm event.
How do we know that?
We know that because technically an over topped levee in not a failed levee, since it withstood the design water level, was over topped but not breached.
In 2005 no levee structure was over topped (if I recall correctly), but several were breached, at water levels below the levee crest elevation (or superstructure or crown elevation).
Thus the levee system failed at several locations below the design water level, in other words below their respective maximum crown elevations.
That is what I read also, a day or two after the storm passed. The maximum water level in Lake Ponchartrain remained well below the crest of the levées. Unfortunately, the link to the tidal records for the period of the storm has long disappeared.
Scarily, since the levees failed so spectacularly during Katrina, where winds of mostly less than hurricane strength were blowing mostly back towards the GOM off the land (ie little in the way of storm surge in Lake Ponchartrain), then the levees would fail far more spectacularly should N.O. catch the strong side of a hurricane (right hand forward quadrant), with onshore winds and storm surge out of the GOM. Even the RHS forward quadrant of a strong tropical storm (70mph winds) with the most potentially damage-causing track could cause levees to fail.. let alone an intense hurricane.
The program to rebuild the levees appears to be suffering from a degree of mismanagement, again?
The program to rebuild the levees appears to be suffering from a degree of mismanagement, again?
I am in a constant love/hate relationship with my home state. With that said, your question should read "the state of Louisiana appears to be suffering from a degree of mismanagement, no?"
That is what I read also, a day or two after the storm passed. The maximum water level in Lake Ponchartrain remained well below the crest of the levées. Unfortunately, the link to the tidal records for the period of the storm has long disappeared.
Scarily, since the levees failed so spectacularly during Katrina, where winds of mostly less than hurricane strength were blowing mostly back towards the GOM off the land (ie little in the way of storm surge in Lake Ponchartrain), then the levees would fail far more spectacularly should N.O. catch the strong side of a hurricane (right hand forward quadrant), with onshore winds and storm surge out of the GOM. Even the RHS forward quadrant of a strong tropical storm (70mph winds) with the most potentially damage-causing track could cause levees to fail.. let alone an intense hurricane.
The program to rebuild the levees appears to be suffering from a degree of mismanagement, again?
Here's a good paper on the Katrina storm surges;
Hurricane Katrina storm surge distribution and field observations on the Mississippi Barrier Islands
See Figure 1 (page 4 of 10)
Remarks by Dr. Ed Link on the Release of Draft Final Report on New Orleans
Hurricane Season Begins With New Plans And Old Levees
The last two links give you some idea of the post-Katrina study efforts (both links are somewhat dated now).
As to the USACE management I have no real informed opinion at this time, I'm just reading the same things you would be reading.
The local NO politics and local NO USACE District and their representatives at the state and national levels makes for a very complicated management situation. Construction delays and/or funding delays or cost overruns futher complicate an already complex management task. And don't forget corruption at all levels.
I am in a constant love/hate relationship with my home state. With that said, your question should read "the state of Louisiana appears to be suffering from a degree of mismanagement, no?"
No kidding. I'm still baffled why they didn't take a direct approach and *fix the problem* by filling it in. I mean cripes, if they can do it at the turn of the 20th century (http://en.wikipedia.org/wiki/Denny_R...le,_Washington), it could be done now. Bigger scale, but we have *slightly* better equipment and practices. Just a wee bit.
Well not *now*, it's too damned late. They had their chance, and they lost it. Oh well, back to the treadmill. Build -> Disaster -> Blame -> Do the same damned thing again.
No kidding. I'm still baffled why they didn't take a direct approach and *fix the problem* by filling it in. I mean cripes, if they can do it at the turn of the 20th century (http://en.wikipedia.org/wiki/Denny_R...le,_Washington), it could be done now. Bigger scale, but we have *slightly* better equipment and practices. Just a wee bit.
Well not *now*, it's too damned late. They had their chance, and they lost it. Oh well, back to the treadmill. Build -> Disaster -> Blame -> Do the same damned thing again.
It's one thing to say it should be done, and quite another to actually do it.
Cut and fill works best where one balances the other, in the case of NO it would be all fill from surrounding areas, creating all sorts of potential problems like for example salt water intrusion.
It's relatively easy to fill in the Crescent Bowl given the ready supply of sediment available 247 from the passing Mississippi River waters.
But moving all those people, removing all the existing infrastructure?
The soil conditions and the surcharge necessary to consolidate a cap would take decades.
It would be much easier to build a whole new island in an undeveloped area.
I personally don't think there will be a NO a century from now due to eventual sea level rise. Southern LA is like southern FL just much flatter and lower.
It's a rock and hard place problem, you're damned if you do, and damned if you don't.
It was the next day when I woke up and watched the news and it was "all change" re. New Orleans..... the levees had failed early that morning, August 30 and massive flooding was starting to inundate New Orleans. It struck me as odd, considering that the storm was by then well inland and had been downgraded to a tropical depression, its far weaker circulation a long way to the North of N.O. I recall interviews with pundits on CNN, ABC, where there was a lot of confusion; I recall the question asked repeatedly "how come the levees broke such a long time after the storm passed"? The answer given was "that there had been a "secondary storm surge" associated with Katrina... and I recall shaking my head in disbelief.. hurricanes do not have "secondary storm surges".. which is why I spent the time to talk with people on WeatherUnderground, looking up the tidal records etc., trying to make sense of this. Not only that, but the major rescue operations didn't really get going until August 31, 49 hours later. Today I dug out my 1995 hard copy journal and reading back the account of the day confirms this.
It's a mere 3 years ago, almost to the day. Does anyone else recall the details of that day, and what was being said on the news? When I look at the current historical record of the storm, all the major sites are now saying that the levee failures, and massive flooding of the city occurred on the actual morning that Katrina made landfall.
I never gave this a second thought until the current (possible) threat of Gustav got me looking at this.
Just like as on 9/11, or the day the war started in Iraq, I can remember exactly the day that Katrina hit. But it is strange how one's recollections of what happened on the day of Katrina differ from the accounts of the timeline in, for example wikipedia etc. I spent most of the day of August 29th watching TV (which is very rare for me), and I distinctly recall the reports that day, most expressing guarded relief, indicating that N.O had escaped a major disaster, and that the levees had essentially held, with only localized flooding from Katrina's heavy rain. The real worry was what happened to the coastline of Eastern LA and MS, which caught by far the worst of the storm, and with all communications out, and the area pretty much inaccessible except by helicopter, everyone was expecting the worst... which turned out to be the case.
It was the next day when I woke up and watched the news and it was "all change" re. New Orleans..... the levees had failed early that morning, August 30 and massive flooding was starting to inundate New Orleans. It struck me as odd, considering that the storm was by then well inland and had been downgraded to a tropical depression, its far weaker circulation a long way to the North of N.O. I recall interviews with pundits on CNN, ABC, where there was a lot of confusion; I recall the question asked repeatedly "how come the levees broke such a long time after the storm passed"? The answer given was "that there had been a "secondary storm surge" associated with Katrina... and I recall shaking my head in disbelief.. hurricanes do not have "secondary storm surges".. which is why I spent the time to talk with people on WeatherUnderground, looking up the tidal records etc., trying to make sense of this. Not only that, but the major rescue operations didn't really get going until August 31, 49 hours later. Today I dug out my 1995 hard copy journal and reading back the account of the day confirms this.
It's a mere 3 years ago, almost to the day. Does anyone else recall the details of that day, and what was being said on the news? When I look at the current historical record of the storm, all the major sites are now saying that the levee failures, and massive flooding of the city occurred on the actual morning that Katrina made landfall.
I never gave this a second thought until the current (possible) threat of Gustav got me looking at this.
I was at the USACE ERDC watching on the lounge TV, waiting, waiting, waiting, ...
... and then it happened, the first report of a levee break, it was reported in the AM on that fateful day (between 9AM and 10AM, I believe).
We lost power later that same day.
The next day I went to work and saw hundreds and hundreds of downed trees.
Power wasn't restored to my area until 10 days later.
Does anyone else recall the details of that day, and what was being said on the news?
I recall that day very well. It sucked. However, news wasn't what I was looking at.
I work for a large hospital organization located in Baton Rouge, Lafayette and North Louisiana.
Extracted from a comment by a seasoned Gulf Coast evacuee:
Evacuating is very difficult. First you have to be let off work. (Many aren't until the last minute). Then you become stuck in evacuation traffic for hours, barely moving. You also must find a hotel or somewhere to stay, rooms fill up quickly for hundreds of miles, and those with pets have an even more difficult time. It is also difficult to predict which areas north are not going to be affected by tornadoes. If your area turns out not to take a direct hit it is a nightmare trying to get back home for work, as you must drive for hundreds of miles through bad weather, downed trees and powerlines.
The forecast track takes Gustav to the west of N.O., the side of the hurricane with the strongest (onshore) winds, heaviest rain and biggest storm surge. The strongest winds will almost certainly come down as it crosses the northern GOM, but it's already a large storm with hurricane force winds extending 70 miles out from the center, and tropical storm force winds 175 miles outward, and the wind field will expand as it crosses the GOM. Even if the eye goes ashore 100-150 miles west of N.O., there will a risk of the city flooding again; The repairs to the levees are far from finished. If it makes landfall close to N.O and to the west... lets not go there (lets us hope that does not happen)... I hope everyone in N.O. gets out of there well before landfall. Unfortunately, yet again, there are a lot of people who, despite the warnings, will be unable to leave, or will find it difficult:
Extracted from a comment by a seasoned Gulf Coast evacuee:
I disagree, did you look at that paper I posted above? Figure 1? The maximum storm surge occurred ~60 km east of the storm track, a close second was the storm surge ~15 km east of the storm track.
Now go back and look at that Figure 1, perhaps the worst path Gustav could take would be for the eye of the storm to track directly along the Mississippi River from Southwest and South Passes landward. Note also the very shallow bathymetry as shown by the visible barrier islands and light blue to almost white colors.
The area with the highest sustained winds will push the most water into shallower and shallower waters, it will be backed into the upper right corner (for the track I've described above), just opposite of NO and Lake Pontchartrain. My guess is that if Gustav passes more than 50 km west of Southwest and South Passes then NO shouldn't see much of a storm surge
I haven't checked the latest NHC tracking predictions, but last I recall the storm would have a relatively steep angle of attack. So if the storm rides up the sediment ridge of the Mississippi River outlet channel that would most likely cause the greatest storm surge for NO. Note also that the Mississippi River-Gulf Outlet Canal is still a POS and hasn't been blocked off yet.
Also note that during Katrina about one meter of the surge was due to the low air pressure which was strongest in the eye wall.
As to getting all the people out of NO New Orleans Orders Mandatory Evacuation Ahead Of Gustav it's mandatory as of 8 AM (or noon) on Sunday. News reports seem to suggest that the evacuation is proceeding much better than the last time (when there wasn't anything to speak of