Katrina H-Wind Analysis, marginal 3 at landfall

[Innotech]

palms also tend to grow in hurricane prone areas and are thus adapted to dealing with high winds that other trees arent designed to withstand. Im sure if the trees around Andrew were all normal hardwoods theyre wouldnt be a single one left. Pine would be the first to go.

[curtadams]

Reading this topic, I realize why all the rest of the countries use 10-min sustained wind instead of 1-min. Perhaps that would work better in situations like these.

I would actually expect the reverse, if the most important goal is to predict damage. I would expect the damage to structures to depend on the largest forces they experience, and I would expect that to depend mostly on the largest local pressure differential set up by interaction with the wind. I don't know how long it takes for a wind to set up a equilibrium pressure gradient on a structure but I would expect it's seconds and certainly less than a minute. So I would expect the most relevant # to be something like 5-second gusts. Of course there are other wind factors, including duration of the peak gust, sustained winds, number of gusts, duration of sustained winds, etc., but I would think that's what you'd want for the single best predictor of wind damage.

[Derek Ortt]

one thing about the palms, they usually remain standing until the wins get up to cat 4, when they tend to snap in half, not uproot

[Kennethb]

Every dig a palm? I have and they have dozens of long strong roots going in all directions through the soil. Hence why unless they were recently planted tend to withstand high winds. Since they thrive in tropical areas they adapted to tropical winds.

Evidentally the roots are designed to hold the palm in the ground. Once you cut all of the roots, they are easy to transplant.

[Frank P]

My neighbor had two palm trees... both were uprooted by Katrina and left holes in his front yard, I found several pieces of my wifes china in the holes left by the palm trees...... one of the palm trees was found on the balcony of my second floor one block north of where my house was....

[NastyCat4]

Katrina was NOT a 3. Most lilkely. it was faulty instrumentation that would be responsible for spurious wind readings. If this tragedy is depicted as a Cat 3, then the scale has absolutely no meaning whatsoever.

[Derek Ortt]

or the common belief that I have seen here of category 3 being the transition category between the non-destructive 1's and 2's and the very destructive 4's and 5's is total hogwash

Perhaps everyone needs to think of the category 2 storms as the transition storms, with the 3's, 4's and 5's being the very destructive ones

[skysummit]

If this is the case, I can think of plenty Cat 3 storms that should be downgraded. I did recovery for MANY Cat 3 and above storms, and I have NEVER seen the type of damage Katrina caused...and I'm talking about wind damage.

[Derek Ortt]

as previously stated before, most cat 3's before, like Opal, only had 1 narrow streak of cat 3 winds, while this one had a large region of 3, with the largest 90KT wind area I have ever seen

[NastyCat4]

There is NO data that can characterize the worst hurricane ever to hit the United States, and the most destructive hurricane as a Cat 3. Sorry, nobody on this board (or anywhere else) would or SHOULD believe that. End of story. Katrina was one of the most deadly disasters in the entire world, and to blow it off as a "3" is to minimize the suffering and decimation it caused. It is far more likely that it was a Cat 5, than a 3. Sorry, I don't buy what was obviously data that doesn't correlate with reality.

[SamSagnella]

Katrina was HUGE.

If Category three winds blew for like 5 hours, that can create 'category 5 damage.' Sure the scale is rather subjective, but yall cant freak out a say that it's 'offensive' to call Katrina a category three. I don't know why everyone here seems to think that a category three is weak...because it isnt. I guess maybe its because we've all be 'spoiled' by the incredible number of major hurricanes since 2002.

[Derek Ortt]

blow it off as a 3?

You must be totally ignorant as to how devastating a cat 3 is. It is a major hurricane for a reason, not a transition hurricane.

There is NO data suggesting anything other than a 3 at Mississippi. The Louisiana landfall is being actively ebated. Dont mention that Katrina was a 4 to some, when all NOAA dropsondes show a 3

[Derek Ortt]

to be honest

saying that Katrina could ahve been a 5 makes as much sense as some of Great One's forecasts.

The data does not lie, and only represents the SUSTAINED winds

I am not sure which way NHC will go for the first landfall in Louisiana. I hope the NOAA data was wrong as I do not want to find out that a marginal 3 did this type of destruction. I hope that it did take a 120KT hurricane that cause what it did to Louisiana

[tornadochaser86]

lets keep in mind when hurricane hunters fly into a storm they are at 3000 ft and the winds are 175mph up there the winds dont always make it to the surface

[wxmann_91]

As I've posted in another thread...

A 918 mb storm will do 918 mb damage.

However you debate it, I believe that the NHC will only move Katrina's winds at landfall up or down 5 mph. The bottom line is that Kat was a Cat 4 at landfall in LA and a strong Cat 3 at landfall in MS.

[kevin]

As I've posted in another thread...

A 918 mb storm will do 918 mb damage.

However you debate it, I believe that the NHC will only move Katrina's winds at landfall up or down 5 mph. The bottom line is that Kat was a Cat 4 at landfall in LA and a strong Cat 3 at landfall in MS.

Huh?? A 918 mb storm will do 918 mb damage?

So a 1004 mb storm will have the same winds regardless of structure or surrounding pressures? Doesn't make sense, because we all know that at different mb's storms have been lower and weaker than others and so on.

[f5]

Katrina also caught the NHC off guard by bringing in that 175MPH surge they thought before as the winds decrease so does the surge

[wxmann_91]

As I've posted in another thread...

A 918 mb storm will do 918 mb damage.

However you debate it, I believe that the NHC will only move Katrina's winds at landfall up or down 5 mph. The bottom line is that Kat was a Cat 4 at landfall in LA and a strong Cat 3 at landfall in MS.

Huh?? A 918 mb storm will do 918 mb damage?

So a 1004 mb storm will have the same winds regardless of structure or surrounding pressures? Doesn't make sense, because we all know that at different mb's storms have been lower and weaker than others and so on.

???

I meant that a hurricane with a 918 mb pressure, regardless of its winds (trust me, they won't be of Cat 2 strength or lower), will do what you would expect a 918 mb hurricane (marginal Cat 5) would do, even if it is not a Cat 5. Likewise, a hurricane with 980 mb pressure you should expect strong Cat 1 damage regardless of wind speeds.

This is meant as a general rule of thumb. If a hurricane stalls and causes flash flooding the intensity does not matter. But otherwise it works well.

[jasons2k]

Pine would be the first to go.

Not necessarily; it is often opined that pines go first because they are not a hardwood tree. Actually pines are very flexible up to a point, and they have a deep root system. We have mostly pine trees here, yet there are many more oaks trees down than pines in this area of after Rita.

For the most part, the pine trees "held up" rather well. It's the oaks, especially water oaks, that took it badly.

[timNms]

Pine would be the first to go.

Not necessarily; it is often opined that pines go first because they are not a hardwood tree. Actually pines are very flexible up to a point, and they have a deep root system. We have mostly pine trees here, yet there are many more oaks trees down than pines in this area of after Rita.

For the most part, the pine trees "held up" rather well. It's the oaks, especially water oaks, that took it badly.

In our area, Katrina took out pines, oaks, and any other kind of tree she wanted, including my palm tree (by the roots) lol.
More pines fell than any other tree. Most of them were snapped off. However, there were many that were uprooted, along with numerous hardwood trees. I was surprised by the number of oakes that were snapped off. Some were weakened already by rot, but the majority of broken ones were solid.