Katrina H-Wind Analysis, marginal 3 at landfall

[Droop12]

What I want to know from everyone is one thing...Where do you guys believe based on what you've seen where were the strongest winds located at landfall? Im speaking of the 2nd landfall. I want to know a city or town or whatever just want to know everyones opinion. I'd say around Pass Christian? The reason I ask is Im going to look at a few of the thousands of aerial photos taken from the NGS and see what the wind damage looks like according to the SSS.

[Derek Ortt]

strongest winds appear to have been enar Bay St Louis

[oneness]

... If they downgrade Katrina, they'd need to downgrade many, many, MANY other storms. I have seen the damage...I have been there for weeks and weeks...and it's clearly cat 4 damage. I'm NOT talking about storm surge, I'm talking about 20-50 miles inland of homes and structures completely gone off their foundations. I don't believe that type of destruction is listed in the classification of Cat 1, 2, or 3 storms. People need to get off their @ss, get out from behind their computers, and get the hell down there to witness it for themselves. Stop listening to the news, stop looking at the pics on the net, and see it for yourself. The damage is very widespread, but there are very small areas of total devistation WELL inland, NOT from surge. I have done recovery for MANY other storms, and this is clearly the worst I have ever witnessed.

That does not by any measure mean this damage was due to sustained cat 4 winds. If the winds are not sustained then it’s not a cat 4—OK? The damage is clearly not from sustained Cat 4 winds as much as people would like to think it is. Trees do not lie about sustained wind speed intensities. The data don’t support a sustained Cat 4 and the evidence of the eyes does not support it either. Show me any area where there are zero trees left standing (and I don't mean softwood pine). When you look around on the ground, or in a photo, look at the building materials then at the trees which remain and the state of each.

I’ve seen what happens to all trees in a sustained Cat 4. ZERO of them survived. I also saw first-hand what a strong Cat 3 did to 60 km wide swathe of hardwood tropical rainforest. Almost nothing of that forest survived save a few bare and tortured trunks, with no limbs whatever remaining on them. It took ~15 years for that forest to recover from the trauma caused by a mature cat 3.

Many people won’t want to face it but the moral of the story is this:

If you want your home or other structures to withstand a strong sustained cat 2 to low cat 3 wind-field, don't ever build with PINE as a structural component. Pointing to wrecked communities of structurally failed homes and businesses, where the major building material was pine does not necessarily imply strong winds, it implies weak structures and homes.

2 cents.

[skysummit]

... If they downgrade Katrina, they'd need to downgrade many, many, MANY other storms. I have seen the damage...I have been there for weeks and weeks...and it's clearly cat 4 damage. I'm NOT talking about storm surge, I'm talking about 20-50 miles inland of homes and structures completely gone off their foundations. I don't believe that type of destruction is listed in the classification of Cat 1, 2, or 3 storms. People need to get off their @ss, get out from behind their computers, and get the hell down there to witness it for themselves. Stop listening to the news, stop looking at the pics on the net, and see it for yourself. The damage is very widespread, but there are very small areas of total devistation WELL inland, NOT from surge. I have done recovery for MANY other storms, and this is clearly the worst I have ever witnessed.

That does not by any measure mean this damage was due to sustained cat 4 winds. If the winds are not sustained then it’s not a cat 4—OK? The damage is clearly not from sustained Cat 4 winds as much as people would like to think it is. Trees do not lie about sustained wind speed intensities. The data don’t support a sustained Cat 4 and the evidence of the eyes does not support it either. Show me any area where there are zero trees left standing (and I don't mean softwood pine). When you look around on the ground, or in a photo, look at the building materials then at the trees which remain and the state of each.

I’ve seen what happens to all trees in a sustained Cat 4. ZERO of them survived. I also saw first-hand what a strong Cat 3 did to 60 km wide swathe of hardwood tropical rainforest. Almost nothing of that forest survived save a few bare and tortured trunks, with no limbs whatever remaining on them. It took ~15 years for that forest to recover from the truma caused by a mature cat 3.

Many people won’t want to face it but the moral of the story is this:

If you want your home or other structures to withstand a strong sustained cat 2 to low cat 3 wind-field, don't ever build with PINE as a structural component. Pointing to wrecked communities of structurally failed homes and businesses, where the major building material was pine does not necessarily imply strong winds, it implies weak structures and homes.

2 cents.

Well then Oneness...what about 190mph Category 5 Hurricane Camille which left THOUSANDS of trees still standing along the coast? Let me guess...we're going to downgrade that storm too. What ever. I'm out of this debate. It's no use.

[Droop12]

I agree oneness. If there was cat 4 sustained winds the tree damage and structural damage would be comparable to Charley. Did anybody see the trees and vegetation after Charley? They were almost completely stripped bare and I dont just mean leaves. I've seen the pics, They dont lie do they? Do the trees and houses further inland away from the surge look different in person than they do in photos posted on the internet? I was going over all aerial shots from around Bay St. Louis and the Pass and yes, areas within a few miles of the water where devastated no doubt about it. But I look inland at aerial photos of neighborhoods, not just one house that look relatively unscathed though Im sure there are probably shingles or siding missing. But I dont see any widespread curtainwall failure or roofs gone from any homes. Heck I see plenty of trailers in fine shape, though I did see a few that were possibly missing a roof. I've yet to see any homes swept clean of there foundation from the winds. Im not downplaying anything, Im stating what I see. I know I dont have the best view from my monitor but I've been all over the MS coast before and I have a pretty good feel for the area. But I guess since Im not there my thoughts are automatically wrong.

[jazzfan1247]

Well then Oneness...what about 190mph Category 5 Hurricane Camille which left THOUSANDS of trees still standing along the coast? Let me guess...we're going to downgrade that storm too. What ever. I'm out of this debate. It's no use.

I wasn't there for Camille obviously so I can't really comment on this as far as the tree damage. But as posted somewhere (maybe earlier in this thread, not quite sure) but Camille had far higher winds at flight level than Katrina did shortly before landfall, so there's no question Camille was way stronger. Now there have been discussions about downgrading the 190 a bit, but we'll have to wait and see what happens.

Perhaps the reason why "it's no use" is that you and those with similar arguments as yours really haven't built up a strong case for yourselves, since you're pitting yourselves against the scientific evidence. It's a shame really; scientists have devoted hours and hours on research and fine-tuning instruments to measure the elements, only to have people like you completely dismiss their findings, without any sound basis whatsoever. These people deserve more respect.

[skysummit]

I do respect the scientists and mets who devote their lives to research, and I do respect their findings. Everyone is entitled to their own opinion whether it agrees with science or not. I wasn't there for Camille either, but all you have to do is compare pictures of each storm. It's visible which storm was stronger. If after all the studying is done, and data still backs up a category 3 for Katrina, I'll go with it....but NOT a "marginal 3 at best". If that's the fact, then Dennis needs to be downgraded to a Cat 1. I was there the day after Dennis hit, and the wind damage wasn't nearly as astonishing as Katrina's damage.

[AussieMark]

I do respect the scientists and mets who devote their lives to research, and I do respect their findings. Everyone is entitled to their own opinion whether it agrees with science or not. I wasn't there for Camille either, but all you have to do is compare pictures of each storm. It's visible which storm was stronger. If after all the studying is done, and data still backs up a category 3 for Katrina, I'll go with it....but NOT a "marginal 3 at best". If that's the fact, then Dennis needs to be downgraded to a Cat 1. I was there the day after Dennis hit, and the wind damage wasn't nearly as astonishing as Katrina's damage.

Dennis was a small system tho. Katrina was a giant.

Also most of Katrinas damage was from the monster surge where as from Dennis it was wind (I think that was the case)

[jazzfan1247]

I do respect the scientists and mets who devote their lives to research, and I do respect their findings. Everyone is entitled to their own opinion whether it agrees with science or not. I wasn't there for Camille either, but all you have to do is compare pictures of each storm. It's visible which storm was stronger. If after all the studying is done, and data still backs up a category 3 for Katrina, I'll go with it....but NOT a "marginal 3 at best". If that's the fact, then Dennis needs to be downgraded to a Cat 1. I was there the day after Dennis hit, and the wind damage wasn't nearly as astonishing as Katrina's damage.

Well you sure have a funny way of showing respect, seeing as how you were pleading to end all debate about this (which is what scientists thrive on, constant debate over evidence) and how you said "people are losing credibility".

Anyways, at least we're getting somewhere, you at least acknowledge that the evidence exists, and that it could be credible. The fact of the matter though, is that at the present time, the best evidence we have PERIOD happens to be the same evidence pointing towards a Cat 3 at the landfalls. It's ok to say a statement such as "although i realize it is scientific data and is credible, i think with more research they'll find otherwise" but so many have resorted to the "I KNOW IT WAS CAT 4" or "this is just BS" without considering the hard evidence at all, and I think this is a big problem.

[Ixolib]

If you want your home or other structures to withstand a strong sustained cat 2 to low cat 3 wind-field, don't ever build with PINE as a structural component. Pointing to wrecked communities of structurally failed homes and businesses, where the major building material was pine does not necessarily imply strong winds, it implies weak structures and homes.

2 cents.

Pine, Fir, Spruce, Oak - WHATEVER you use, just be sure to use hurricane straps where the roof ties into the top plate and where the walls tie into the sill plate. And as been proven in many cases here, hurricane clips on the plywood roofs did wonders too. Weak structures are often the result of shoddy workmanship where corners are cut and added materials are often left out, many times in spite of the building code.

I have first-hand observation of these two preventive measure in action. Those that had 'em generally did pretty good unless a pine tree came crashing through (or they were overtaken by surge). Those that didn't had significantly more damage.

[oneness]

If you want your home or other structures to withstand a strong sustained cat 2 to low cat 3 wind-field, don't ever build with PINE as a structural component. Pointing to wrecked communities of structurally failed homes and businesses, where the major building material was pine does not necessarily imply strong winds, it implies weak structures and homes.

2 cents.

Pine, Fir, Spruce, Oak - WHATEVER you use, just be sure to use hurricane straps where the roof ties into the top plate and where the walls tie into the sill plate. And as been proven in many cases here, hurricane clips on the plywood roofs did wonders too. Weak structures are often the result of shoddy workmanship where corners are cut and added materials are often left out, many times in spite of the building code.

I have first-hand observation of these two preventive measure in action. Those that had 'em generally did pretty good unless a pine tree came crashing through (or they were overtaken by surge). Those that didn't had significantly more damage.

That is (of course) a factor, but it's not just bracing and strapping which is involved though and it’s misleading to think pine's well known weakness can be easily compensated for via bracing and strapping. Pine trees go down or snap first in low cat hurricanes because pine trees are a weak timber which contains many natural flaws, cracks and knots. People build with pine because they have less money with which to build a genuinely strong structure with similar floor area. (i.e. they are undermining the strength of the building from the outset, and if short of $$$ are more prone to cutting-back further on 'costs', where possible. When whole communities or subdivisions then build structures out of pine the structures are incorporating a great deal of intrinsic structural weakness. For example, one can screw down a roof baton with a 90 mm baton screw into a pine truss and you can often stress it loose again (cause the thread to pull out of the truss grain) with one or two well placed solid boot kicks. I've done it many times and seen many lengths of so-called "structural-grade" pine fail dismally. The result is that people see terrible images of structural failure yet don't realise that even a cat 1 or 2 can do this with little problem to a pine-based building. Thus people tend to think the destruction they see is caused by a major storm, when in fact, a low cat storm can devastate most pine structures. There was a classic (Rita?) image posted in here last week showing a pine gable roof which was torn to pieces, but with two large pine trees still standing in the middle distance behind the wrecked home! i.e. approx cat 1 winds destroyed that particular pine-based home. A lesson is repeated until the lesson is learned and if pine structures have become the norm in vulnerable areas, then you can expect to see land-falling Cat 2 hurricanes causing disproportionate and very expensive structural damage levels for decades to come as such structures and homes proliferate and their intrinsic weakness points degrade and exacerbate as they age. Pine, in the final analysis, is not a cheap material to build with in hurricane prone area.

[Droop12]

Skysummit, where were you exactly after Dennis? I know at my house, the damage from Dennis was worse then Ivan and Ivans winds lasted for nearly 7 or 8 hours where as Dennis's lasted about 45minutes to an hour. My neighbors who lost a total of 5 or 6 shingles during Ivan lost about half of all the shingles on the entire roof during Dennis. Its obvious that, in a much smaller area, Dennis's winds were worse then Ivan. I believe Derek agrees with that to. It all has to do with pressure gradient, Ivans pressure was around 942mb at landfall and Dennis was around that vicinity to, but Dennis's core was much smaller then Ivans, thus the winds were probably higher. It didnt help that a ton of convection blew up on the NW quad of the eyewall and helped bring down the stronger winds from aloft. IMO, Katrina's sustained winds were probably the same as Dennis's, about 120 - 125mph but over a MUCH larger area.

[HurricaneBill]

I don't know if it's right to compare Katrina and Charley. Charley had a much smaller surge.

I wonder though, would Charley have been far more destructive if accompanied by a large surge?

What was the surge with Charley? 7 ft?

[timNms]

From NWS Jackson, MS. You should read the whole report. It's very interesting. Wind gust in laurel, MS recorded at 110 mph. (instrument failed due to power outages, if I read correctly)

http://kamala.cod.edu/offs/KJAN/0510031623.wwus41.html

POST TROPICAL CYCLONE REPORT...HURRICANE KATRINA NATIONAL WEATHER SERVICE JACKSON MS 1120 AM CDT MON OCT 3 2005 DESTRUCTION IN THE PATH OF HURRICANE KATRINA HAS BEEN WIDESPREAD AND OVERWHELMING. CATASTROPHIC DESTRUCTION WAS LEFT ACROSS THE GULF COAST AND PARTS OF SOUTHEAST MISSISSIPPI. SEVERAL VISUAL SURVEYS WERE MADE BY NWS PERSONNEL ACROSS PORTIONS OF CENTRAL...EAST-CENTRAL AND SOUTHEAST MISSISSIPPI. THESE SURVEYS INDICATED WIDESPREAD DAMAGE COMPARABLE TO F1 TO F2 TORNADOES...WITH AREAS BORDERING ON F3 TYPE DAMAGE. THE MOST EXTENSIVE DAMAGE...FROM THE SURVEYED AREAS...IS ROUGHLY LOCATED SOUTH AND EAST OF A PURVIS TO COLLINS TO NEWTON TO MERIDIAN LINE. AREAS NORTH OF I-20 DUE HAVE CONSIDERABLE TREE DAMAGE...COMPARABLE TO AN F1 TORNADO...BUT THE DAMAGE IS NOT AS WIDESPREAD LIKE ACROSS SOUTHEAST MISSISSIPPI.

Here's an FYI. (Note the comment in the NWS's quote above of bordeline F3 damage. On a map of MS the cities listed above are in the following counties Lamar, Covington, Newton, Lauderdale) http://www.usatoday.com/weather/wfujidef.htm

F-0. Light damage. Wind up to 72 mph. Some damage to chimneys; breaks branches off trees; pushes over shallow-rooted trees; damages sign boards.

F-1. Moderate damage. Wind 73 to 112 mph. The lower limit is the beginning of hurricane wind speed; peels surface off roofs; mobile homes pushed off foundations or overturned; moving autos pushed off the roads; attached garages may be destroyed.

F-2. Considerable damage. Wind 113 to 157 mph. Considerable damage. Roofs torn off frame houses; mobile homes demolished; boxcars pushed over; large trees snapped or uprooted; light object missiles generated.

F-3. Severe damage. Wind 158 to 206 mph. Roof and some walls torn off well-constructed houses; trains overturned; most trees in forest uprooted.

F-4. Devastating damage. Wind 207 to 260 mph. Well-constructed houses leveled; structures with weak foundations blown off some distance; cars thrown and large missiles generated.

F-5. Incredible damage. Wind above 261 mph. Strong frame houses lifted off foundations and carried considerable distances to disintegrate; automobile sized missiles fly through the air in excess of 100 meters; trees debarked; steel-reinforced concrete structures badly damaged.

[docjoe]

Skysummit, where were you exactly after Dennis? I know at my house, the damage from Dennis was worse then Ivan and Ivans winds lasted for nearly 7 or 8 hours where as Dennis's lasted about 45minutes to an hour. My neighbors who lost a total of 5 or 6 shingles during Ivan lost about half of all the shingles on the entire roof during Dennis. Its obvious that, in a much smaller area, Dennis's winds were worse then Ivan. I believe Derek agrees with that to. It all has to do with pressure gradient, Ivans pressure was around 942mb at landfall and Dennis was around that vicinity to, but Dennis's core was much smaller then Ivans, thus the winds were probably higher. It didnt help that a ton of convection blew up on the NW quad of the eyewall and helped bring down the stronger winds from aloft. IMO, Katrina's sustained winds were probably the same as Dennis's, about 120 - 125mph but over a MUCH larger area.

good post. i live in santa rosa county and had the eyewall go over my house (my new roof loks real nice). there is no doubt Dennis produced higher sustained winds here than Ivan did but as you say the small size of the storm and the brevity did not effect as large of an area. I am confident the milton and pace areas had a short period of solid cat 3 winds and I think the damage bears this out. BTW i guess I am qualified to make this assumption as I was here for Dennis therefore I "understand"
Of course more importantly recorded data that I have seen seems to support this.
docjoe

[docjoe]

I do respect the scientists and mets who devote their lives to research, and I do respect their findings. Everyone is entitled to their own opinion whether it agrees with science or not. I wasn't there for Camille either, but all you have to do is compare pictures of each storm. It's visible which storm was stronger. If after all the studying is done, and data still backs up a category 3 for Katrina, I'll go with it....but NOT a "marginal 3 at best". If that's the fact, then Dennis needs to be downgraded to a Cat 1. I was there the day after Dennis hit, and the wind damage wasn't nearly as astonishing as Katrina's damage.

SS ..where were you the day after Dennis.If you were in Pensacola then you did notget to the heart of the storm. just curious

docjoe

[skysummit]

To everyone who wanted to know where I was after Dennis, I was everywhere from Gulf Shores, to Destin...primarily in the areas between Perdido Key and Navarre. I traveled down just about every highway in that primary area, even along Santa Rosa Island where it was closed to the public. I had to do damage and assessment. There was a lot of damage, especially in the Navarre area, but it wasn't any near as bad as what I thought it would be. Pensacola, P.B., and Perdido Key barely looked like it got touched. Most of the damage that I saw there was left from Ivan. As I went further east on Hwy 98, there was a very small area near Navarre that showed to have the worst damage, but it still wasn't anywhere near as bad as I thought it would be.

[Normandy]

Well then Oneness...what about 190mph Category 5 Hurricane Camille which left THOUSANDS of trees still standing along the coast? Let me guess...we're going to downgrade that storm too. What ever. I'm out of this debate. It's no use.

I wasn't there for Camille obviously so I can't really comment on this as far as the tree damage. But as posted somewhere (maybe earlier in this thread, not quite sure) but Camille had far higher winds at flight level than Katrina did shortly before landfall, so there's no question Camille was way stronger. Now there have been discussions about downgrading the 190 a bit, but we'll have to wait and see what happens.

Perhaps the reason why "it's no use" is that you and those with similar arguments as yours really haven't built up a strong case for yourselves, since you're pitting yourselves against the scientific evidence. It's a shame really; scientists have devoted hours and hours on research and fine-tuning instruments to measure the elements, only to have people like you completely dismiss their findings, without any sound basis whatsoever. These people deserve more respect.

Sky raises a very valid point. Its very fine and dandy to downgrade Katrina to a Cat3, because I will agree most of the damage was from surge. But dont dare call Camille a 190mph Cat 5 when the damage from both storms are very very comparable. I even question if Camille was a 5, and if it was I suspect it was far far weaker than Andrew.

[Matt-hurricanewatcher]

If it was a weak cat3 like Rita. A few days ago I would of said no way a cat3 can do this. But looking at the flooding/surge Rita did on satellite pics...I'm truely Amazed. Look at those satellites in the other forum here. I'm shocked! Its almost worst then Katrina. Rita was not the little sister like I thought.

[Derek Ortt]

the lesson of this season is that it does NOT take a category 4 or 5 to cause severe damage. Before this year, cat 3 has often been thought of as the transition category between nuisance and destructive. The last 2 years have shown that the transition category in reality is category 2. Cat 1 hurricanes tend to be more nuisance, except in mountain regions, cat 2 is the bridge from this to total devastation, which starts at cat 3 (that is, regions experiencing true cat 3 conditions, not people thinking they went through a cat 3, like many said they did with Jeanne, but really only receive cat 1 winds)