Katrina H-Wind Analysis, marginal 3 at landfall

[Stormcenter]

[quote="jujubean]
It seems as if this little debate has turned into my storm was stronger than yours stuff

That's not really the point. When people claim Storm A had Cat. 4/5 wind damage, a comparison must be made to a documented Cat. 5 such as Andrew or a Cat. 4 such as Charley. That's the basis for the comparison. It's not a contest per se, as Derek has exhaustively pointed out, it's essential so that we can make adequate plans in the future.[/quote]

What plans? You either leave or stay and rebuild. You cannot plan for a cat. 3,4 or 5 hurricane. All you need to do is take what think is important and leave.

[Stormcenter]

I agree. The angle of landfall is paramount. Look at Georges at Cat 2 with a 14 foot storm surge in 1998. But surge aside, when has a Cat 3 storm ever caused a 25-30 ft. storm surge, at any angle? A good example is Lili in 2002. Lili reached 145 mph/Cat 4 status in the central Gulf before weakening to a 105mph/Cat 2 at landfall in LA. There was no huge storm surge there. The surge in Katrina reflects it 923 mb pressure, not a dramatically weakened hurricane. Even Ivan was said to have 135 mph winds at landfall and Ivan's surge wasn't like Katrina's. The debate will continue but I would really like to know how a 125 mph storm could totally obliterate 80+ miles of coastline in Mississippi regardless of it's windfield size.

Another GREAT post.

[Stormcenter]

Actually most of that damage was done by numerous strong tornadoes spawned by Andrew and his winds. There were many homes in Homestead that were still standing after the storm with moderate damage.

Most tornadoes in a hurricane are very brief and small in stature. Typically, hurricanes don't produce mile-wide tornadoes as seen in the Plains. Some of the damage was created by tornadoes, but not for blocks and blocks both wide and deep.

Not in Andrew. Did you see the damage one of his "small" tornadoes did in Laplace, LA?

[jasons2k]

What plans? You either leave or stay and rebuild. You cannot plan for a cat. 3,4 or 5 hurricane. All you need to do is take what think is important and leave.

If the information isn't accurate, people will stay and risk their lives. Many people on the MS Gulf Coast stayed for Katrina thinking that Camille was the all-time worst. That proved to be a fatal mistake for many. They'll do the same in the future if they are misinformed that Katrina was a 5 @ landfall when it wasn't.

[Recurve]

I live in Gulfport, MS; been here all my life. My husband and I swam out of our house at 0930 and rode out the majority of the storm in a neighbor's boat. I saw pine trees bend over with the wind close enough that if I reached up far enough I could have touched the tops. I was hit with debris at was going at least 50MPH. We were covered from head to toe with bruises and abrasions. Katrina was a combination of a large mass of energy with high winds and lots of water. Cat 3, Cat 4 or Cat 5, it doesn't matter. It was a disaster unlike anything seen before and hopefully is not a precursor for events in the future. I don't care what the pressure was at landfall, don't care if gusts were 100 or 200 MPH. I do care that my home is gone and precious momentoes are wet and covered in sluge. I've enjoyed reading this board for several months, but don't really post much. All I am saying is that instead of debating how hard did a storm hit, let's figure out a way to better prepare people. Thank you

You are so right, and I know everybody feels great sympathy for what you are going through. I hope you get all the help you need for coping and rebuilding.

I can try to help with your call to action: "Let's figure out a way to better prepare people."

To do that, we will continue having difficult discussion about observation data, storm structure, and damage, and hypothesizing to reconcile seeming contradictions.

People are overheated because of course it's been an emotional trauma for so many. But to prepare the public better, with information and building design and more thorough understanding of storms, we need more information about the actual data, not less. We need this discussion to continue, with moderation and rationality, not shouting. Maybe we can better understand how a hurricane of X windspeed does XX damage. It's clear that a lot of people are unconvinced a Category 3 hurricane can cause vast destruction.

We'd be disrespecting the loss of everyone in Katrina's path if we don't lay out facts and try rational analysis.

At least we're not trying to figure out whose "fault" Katrina is...

[Stormcenter]

there were not tornadoes in the eye wall

As for saying its not important how strong it was, storm center, I am so glad you are not in emergency management. We must know precisely how strong Katrina was, so that we are better prepared the next time a Katrina like storm comes, be it a 3, 4, or 5

Perpared for what? You just get the hell out of there. Who in the world is "prepared" for a cat. 4 or 5 hurricane? Are you suggesting everyone builds there homes with concrete blocks and ride the storm out? You will never be prepared for a cat. 4 or 5 hurricane.

[jasons2k]

Actually most of that damage was done by numerous strong tornadoes spawned by Andrew and his winds. There were many homes in Homestead that were still standing after the storm with moderate damage.

Most tornadoes in a hurricane are very brief and small in stature. Typically, hurricanes don't produce mile-wide tornadoes as seen in the Plains. Some of the damage was created by tornadoes, but not for blocks and blocks both wide and deep.

Not in Andrew. Did you see the damage one of his "small" tornadoes did in Laplace, LA?

From the NHC:

4. Tornadoes
There have been no confirmed reports of tornadoes associated with Andrew over the Bahamas or Florida. Funnel sightings, some unconfirmed, were reported in the Florida counties of Glades, Collier and Highlands, where Andrew crossed in daylight. In Louisiana, one tornado occurred in the city of Laplace several hours prior to Andrew's landfall. That tornado killed 2 people and injured 32 others.

That was a feederband tornado and sometimes they can be the exception to the rule. Furthermore, there were NONE reported in Florida. The damage photos were from the eyewall.

[jasons2k]

Recurve, very well stated and the very essence of this discussion.

[Derek Ortt]

storm center,

that post was the WORST of the day, by far (actually, none of yours have added anything scientific to the debate, to be brutally honest)

We must know how to prepare so we know how far inland to evacuate, do we do 3 miles, 5, or 10 and for what category of hurricane do we enact these plans

[MGC]

I can show you in person where a mesovortice in the eyewall of Katrina crossed I-10 and into Diamondhead. The swath of trees downed is indicative of rotation as trees in this area are down in multiple directions opposed to the downing by the straight line winds. I've observed this tree fall pattern in many a post tornadic event I've witnessed over the years. Katrina produce multivortices just like Andrew did without question, and thus likely produce wind streaks approaching cat-4.....MGC

[Derek Ortt]

no question that there were mesovotrs in the eye wall, which locally can enhance the winds by as much as 30 m.p.h.

[Aslkahuna]

I have seen lightning in typhoons and there's the famous Jim Leonard video of typhoon Omar on Guam where lightning strikes close by to the vehicle he was in. One thing about Katrina is that the storm had an extraordinary amount of lightning in it out over the GOM and the eyewall had lightning even up to landfall. Out over the GOM, not only the eyewall and outermost band (the two areas where lightning is most common in intense Tropical Cyclones) but also the interior bands had quite a bit of lightning in them. Rita OTOH followed a more typical lightning pattern. As
Katrina weakened the lightning in the interior bands disappeared. Satellite derived cloud top temperatures in Katrina were very cold so we had some really high tops in that storm indicating very strong convective processes were ongoing there at time.

Steve

[Genequte]

Recurve, thank you for you comments. I think the biggest killer of this storm was something that I, too, suffered from. Apathy and arrogance. I had been through Camille, a "once in a lifetime storm!" and Katrina was "only" a cat 3. So, like many of other Camille survivors I've talked to, we thought, some wind, downed trees and weeks without power, been there done that, we survived Camille and we will be fine. We were wrong. This simple misconception alone cost many people dearly. Ihave been here through every hurricane since Betsy. I always stayed home; never again. The LA and MS gulf has had many close calls with Ivan, Emily, etc and so many "false alarms" that people began to ignore the warning to evacuate. In some respects you can never truly prepare. To me the solution is simple, if a hurricane is coming, leave. Put aside a few dollars each week and build an evacuation fund and when the time comes, leave. If you don't have the funds to leave, get to a strong shelter. If you insisit upon staying in your home, tatoo your social security number on your arm, (for easier identification), carry a heavy duty rope,( to tie yourself to a large tree when your house blows away) and most importantly make sure someone knows where you are( so family and friends do not have to post your picture on a web page looking for you). Not a very PC post, but as accurate as I can be with everything I have seen and been through.

[Stormcenter]

storm center,

that post was the WORST of the day, by far (actually, none of yours have added anything scientific to the debate, to be brutally honest)

We must know how to prepare so we know how far inland to evacuate, do we do 3 miles, 5, or 10 and for what category of hurricane do we enact these plans

I wasn't trying to add ANYTHING scientific to the debate just stating the FACTS. Katrina was the most destructive hurricane to strike the U.S. coastline in terms of loss of life and property in the last 100 years. What else is there to debate about. Who really cares whether she was a cat 3,4 or 5? You will never be able to prepared as how far inland to evacuate because every hurricane is different and some weaken inland earlier than others. There is NO way to determine which storms will do that. Sorry to say we didn't learn it with past storms and we won't with Katrina.

[Derek Ortt]

well,

facts are based upon science

and not caring what it was at landfall, as I said earlier, I am so glad that you are not in change of emergency management as the next time a 3 was heading toward MS, you would think that it wasn't oing to be as bad as Katrina based upon your comments here

[docjoe]

People often try to hide their ignorance behind bombastic and overstated outbursts. Saying that no need exists to fully understand and quantify storms like Katrina because nothing could be done anyway is simply smoke and mirrors. I do not know if you have truly experienced the before, during, and after of a major hurricane. From my personal experience preparation is an absolute must. Preparation will not in most cases protect your beachfront home from 15+ surge or your inland home from a 140MPH+ downdraft. However it will go one hell of a long way in deciding how far to evacuate, if you have food and water, if your shelter is strong enough, contacting your insurance company , etc. I can gurantee that the next time an Ivan or Dennis or worse comes along my community will weather the storm better due to an understanding of how to prepare. I agree with Derek....thank the Good Lord above you are not involved in emergency management.

docjoe

[Stormcenter]

well,

facts are based upon science

and not caring what it was at landfall, as I said earlier, I am so glad that you are not in change of emergency management as the next time a 3 was heading toward MS, you would think that it wasn't oing to be as bad as Katrina based upon your comments here

I guess you haven't thoroughly read my post if you can make that comment. I am the one saying it makes NO difference whatsover if it's a Cat.3,4 or 5 huricane heading my way I'm out of here. I just left for Rita and I'm glad I did even though we lucked out. Katrina "should" be the wake up call to ALL that reside along the Gulf coast and Atlantic seaboard.
My debate was with anyone thinking she was anything less than a cat. 4 with the pressure reading she had at landfall. I'm sorry if you or anyone else has a problem with that but that's the way I feel.

[MGC]

There is little one can do to prepare for a monster like Katrina. Sure, you can have your hurricane kit. Which BTW is totally inadequate. I had weeks worth of supplies ready. Only thing I wish I had a greater stockpile of was gasoline. Cash was useless after Katrina. I don't recall spending any money for around a week after Katrina. Nothing was open to buy. We traded some gas for some yard work from some kids who needed the gas for their car. I still remember the sick feeling I felt waking up Sunday morning and realizing a Cat-5 was gonna hit near me. We had made some preliminary preprations Sunday just like we did for Ivan and Dennis. We were on the road by 1pm Sunday afternoon. Really the only thing you can do is leave. The hurricane will take what it wants and there is nothing you can do about it. All you can do is save you life and leave. Yes, complacency cost a lot of lives here on the coast.....MGC

[djtil]

dont know if this has been posted yet.....appears the cat 3 push is gaining steam. obviously the surge in ms wasnt indicative of a cat 3...but surge does not define categories......

as for the cat 1 in new orleans part...this is fairly obvious based on wind damage....


http://news.yahoo.com/s/chitribts/20051004/ts_chicagotrib/katrinaspunchfacesdowngrade

[Derek Ortt]

not a surprise at all

the data is starting to be very conclusive that Katrina did weaken to a category 3 hurricane just before making landfall