Great Thread: Truly Learning About Storms (EDITED)

[Scorpion]

Homestead had to have gotten Cat 5 winds. The place was levelled to the ground. I still believe Camille was a Cat 5, 145-150 kts, at landfall.

[MiamiensisWx]

I've got friends in Boca Raton, a good 75-80 miles north of Andrew, who said they've 'gone through Andrew', and then refer to its Cat 5 status. It isn't that they are stupid...they are just ignorant. They haven't learned how hurricanes work, how they are structured, the diminishing winds farther from the eye, the difference between sustained and maximum winds, etc.

I would venture a guess that the majority of the public is the same...so how damaging is it when media hypes the SS categories to a television viewing audience, considering that just within that viewing area there could be areas experiencing far different effects from the same storm?!

I wish they would start explaining the storm's size, forward speed, eyewall size, hurricane windfield, and other factors when warning the public about an impending hurricane...maybe the general public would have much greater respect for a Cat 1 hurricane if they understood that the gusts can still reach cat 5 intensity.

I've tried to sober my friends by letting them know that what they thought was amazing destruction last year during Frances was actually no more than high tropical storm force winds. And when they mention Wilma as a Cat 3, I try to clear up that a strong majority of areas within the eye path saw no more than Cat 1 sustained winds, with a few areas seeing some Cat 2s during the worst bits.

They see my lips moving, but I don't know if they understand the words that are coming out of my mouth! I hope for their sake they start respecting the 1s and 2s, because if we ever get a sustained 3 or 4...there may be alot more interviews with people in trees whose houses made it through Wilma!

I agree. Those are excellent points. In addotion, there should also be more attention devoted to that certain areas where buildings, structures, trees, and other objects (e.g., high-rise condos) can create a "windtunnel" effect (what you mentioned), resulting in higher windspeeds than surrounding areas. Also, areas near or on open areas (e.g., near the Everglades, on barrier islands, next to airports or fields, and similar situations) may have higher winds than surrounding areas due to surrounding open spaces, resulting in less friction reducing the winds.

Second...as to the land friction, I am not a scientist or professional, so I cannot intelligently argue this point. However there are other factors that may contribute to higher winds in particular areas versus others. For example, it seems that areas near wide fields, airports, vast parking lots, or other wide-open areas took more damage being exposed to undiluted winds over a long stretch of open land versus homes or structures surrounded by trees, other houses, buildings, etc. Many people's homes were saved from the maximum winds against structural walls because of neighbor's houses, trees, etc which took some of the impact out of the wind. So if your house is on a lake, golf course, or near an airport, it seems likely that the force of the wind striking your house or property may have been stronger than neighboring areas.

Also, areas around high-rise buildings, or in residential areas where the streets may have run parallel with the wind direction, might have allowed winds to 'funnel', which can strongly increase the windspeeed for structures between or at the end of these corridors. Drive down A1A on a windy day and feel the difference in wind between open stretches and passing by an opening between condos and you'll know what I mean. So your location and surroundings should be taken into consideration as to the affect on the winds.

[f5]

Homestead had to have gotten Cat 5 winds. The place was levelled to the ground. I still believe Camille was a Cat 5, 145-150 kts, at landfall.

NHC said in their report that Homestead got winds between 110-150 mph sustained those CAT 5 winds stated in the report were confined to the islands offshore.NHC also told homestead residents not to "POO-POO"a lesser storm beacuse a CAT 5 made landfall

[MiamiensisWx]

NHC said in their report that Homestead got winds between 110-150 mph sustained those CAT 5 winds stated in the report were confined to the islands offshore.NHC also told homestead residents not to "POO-POO"a lesser storm beacuse a CAT 5 made landfall

The NHC said that the Category Five sustained winds in Andrew were mainly along the shoreline of and on Biscayne Bay at the time of landfall. There is also a slight possibility of isolated Category Five sustained winds in the northern eyewall. However, most of the sustained Category Five winds were fronting and over Biscayne Bay.

[MiamiensisWx]

NOTE - I edited the title of this thread because it is quickly turning into a truly great learning thread about storms and how there are many factors. I still have things to learn!

By the way, I apologize for the previous title of this thread and for not researching more on Camille/paying too much attention to pictures for damage...

[caribepr]

People expect when they hear 120, 130, 140 150 160 to see everything gone and air doesn't move like that. It forms eddys, bumps up against other things and flows around it. After Andrew I was kind of shocked to see that the storm, while it destroyed quite a bit, there would still be neighborhoods where everything was gone except for a couple houses with nary a scratch.

Wind is capricious.

Thank you...that was the point I was intending to bring up as I read through the posts...but you got there first.

Though it is awfully traumatic going through a hurricane, and the stress, adrenaline, and many other factors can make the experience not only hellish but also become a bit of a big fish story for those who make it through. We all want to believe that the storm we experienced was big and bad, mostly to gain a foothold over our fears of how much worse it could be. Hey, I went through Camille, and it was a Cat 5...so I can go through anything!

Too many people suffered from that very mentality in MS and the number of people after the storm being interviewedd after clinging to a tree 25 feet up watching their house disappear made the same statement "my house survived Camille...I thought I'd be OK".

What you said is part of that factor...few take into consideration the fluctuations within a storm...the little nuances that create stronger and weaker winds, the various contributory factors such as landscape, building construction, location, that can vastly alter the effects of the same storm just a few hundred yards apart.

Just because a storm is rated with sustained Cat 5 winds...it doesn't mean that all locations within the hurricane windfield are receiving those Cat 5 winds, nor are most locations receiving the sustained winds all the time during the storm. Even a sustained measurement may have only been recorded in one location, while most others saw less. And the difference in gusts in any one area versus another can vary greatly...one area can get a gust 20MPH over the sustained winds, while another sees a 70MPH increased gust. With microbursts and tornadoes thrown in, you just don't know what you are going to get in any part of the storm.

It is even conceivable that someone in the middle bands of the storm, experiencing sustained Cat 2 winds, might experience a particularly powerful gust of 160 or 170 MPH which causes severe damage exceeding the damage suffered by someone else who went through the eyewall with sustained Cat 4 winds but without that ferocious gust.

I think that using damage as an indicator of category is a bad idea, and will always result in inaccurate measurements of a storm's intensity. With so many other factors, from construction, building codes, surrounding land friction or impediments, availability of destructive debris, and storm surge contributing to the amount of damage suffered in a particular area, the damage just cannot accurately portray the true windspeeds sustained in a given area.

Why more people can't understand the destructive potential of any hurricane instead of putting so much faith into the SS categories, I'll never understand. Knowing that my house might survive a Cat 4 hurricane with little or no damage doesn't mean it will survive a Cat 1 storm untouched. It just means that I was lucky. The next Cat 1 that comes through might drop a microburst or tornado through my area, and my Cat-4-surviving house could be gone. To have stayed along the MS coast with Katrina bearing down just because you made it through Camille seems (especially in hindsight) like a terrible misunderstanding of the nature of a hurricane...Whether Camille was a 4 or a 5 doesn't matter...it was big and destructive, and any person or structure that survived it did so partially through preparation and construction, but mostly on luck. As many found out in Katrina, the lesser-rated storm ended their lucky streak.

Thank you. Now I don't have to quote and post. It's a *your house is gone, mine stayed and we were one block from each other* sort of thing here. Facts, numbers, while certainly important and revelant for science and the understanding of what is going on and what is potentially ahead of us, are made moot on a personal level (and I know I go to the personal level, as I am NOT a met, or a met in training and I know that sort of thing is fascinating to decipher for many here...and I've learned a lot from this...however...) during a hurricane.
As someone posted, no one is outside during the event with instruments while their particular location is being battered.
What is difficult for me, while the debate is interesting and informative, is the sort of (for those who don't get into it, that caveat) generalization of a hurricane over a particular area, regardless of how big it may be - Katrina vs. Camille as an example.
Think in tornado terms, maybe it will help - a swath through one area but totally untouching another - except in a hurricane, it's happening over a greater field, with more warning, regardless of HOW PERFECTLY OR IMPERFECTLY THAT WARNING IS GIVEN.
Andrew is a good example (and one of the best I know personally, despite building codes, etc - not going there). It was easy to see, driving along, the line of destruction from worst to less worse - but the anomolies - five houses untouched, two wrecked, etc., that IS the nature of the immediate moment of these storms.
Surge, wind - these factors, overall (which is the unfortunate part and is, in my opinion, what leads to these discussions due to the complexity of area and impact) will NOT be calculated by facts except in hindsight, if even then, due to the above - what happens next will happen next and it WILL be different and it WILL be real, and new stats will be the outcome, along with new realities for those whose lives are changed forever because of a storm.
It can all be racked up in numbers. It can all be argued until doomsday. But the reality is - if something huge is headed your way, be prepared, assume nothing from history, and if you don't like those realities, get the hell away from hurricane prone areas. Otherwise, assume you ARE in line. (this is my non-into-the-numbers take, even though I do enjoy learning from what you all say).
And if you are not in hurricane prone areas and simply enjoy *tracking the storms* remember, each street has a different reality, each town, each coast. Except now for the horrible realities of whole towns washed away...stat that.

[Normandy]

Until someone shows me pictures of Andrew-like wind damage from Camille, I will still say Camille was either a strong 4 or a marginal 5 (like 160 at most).

[Ixolib]

Well, having experienced both first-hand, I can surely say that the winds in Katrina were NOT nearly as extreme as those I experienced in Camille - and I was in the exact same location for both.

I understand that. I'm just making a point that one can't tell the difference between Cat 3 or 4 sustained winds and Cat5 sustained winds. Your overall experience can certainly be judged...but nobody can say that something is a 125 mph sustained and another is 160 with certainty...and noone can certainly say that one wind is 140 and another is 160...just ont possible unless you have equipment. The main reason is you aren't looking outside at the stuff blowing around...but trying to save your life and hiding under something.

Yep AFM - I agree on all points!! The human being can comprehend a sense of "stronger" vs. "weaker" - as in my case with Camille & Katrina - but no human that I'm aware of can guage specific and exact wind speeds without the proper tools to do so...

As for looking outside - we surely did that in Katrina. Keeping a constant eye on the surge was the O-N-L-Y thing on our minds in those few hours. And since Camille was at night, seeing anything at all was questionable at best. Bottom line - the only reason Katrina was worse than Camille is easily the surge - not the wind.

Here's a couple of pics from my front porch - facing north - during Katrina. We did NOT see this in Camille!!

[rtd2]

ixolib....If I remeber correctly your just outside the base correct? Keesler had water in places it had NEVER reached. there was also some new buildings with severe roof damage. The map below shows approx where and how deep the water was (You may have already seen this?) I was sheltering just off Larcher Blvd about 3 blocks from the BX/Commissary which got 8-10 ft.! I have some wind damage photos somewhere on a disk

http://www.fema.gov/hazards/floods/recoverydata/maps/katrina_ms-i24.pdf

http://www.fema.gov/hazards/floods/recoverydata/maps/katrina_ms-i25.pdf

http://www.fema.gov/hazards/floods/recoverydata/maps/katrina_ms-j24.pdf

[MGC]

The wind field of each hurricane is different even if they have the same central pressure. Katrina and Camille were simular but different beasts. Looking back I'd rather have Camille hit here again than Katrina. I've seen the damage from both hurricanes and Katrina left Camille standing by the curb. Camille had stronger winds than Katrina but Katrina's water did way more damage than Camille. The SS scale was developed to show estimated damage potential a particular hurricane possesses.

From the NHC website:

Category Five Hurricane: Winds greater than 155 mph. Storm surge generally greater than 18 ft above normal. Complete roof failures on many residences and industrial buildings. Some complete buildings failures with small utility buildings blown over or away. All shrubs, trees, and signs blown down. complete destruction of mobile homes. Severe and extensive window and door damage. Low-lying escape routs are cut by rising water 3-5 hours before the arrival of the hurricane. Major damage to lower floors of all structures located less than 15 ft above sea level and within 500 yards of the shoreline.


Katrina met all of the above criteria except sustained winds. Other criteria was exceeded by a large margin. I have the pictures to prove the damage. Katrina made a joke of the SS scale and it needs to be revised......MGC

[rtd2]

The wind field of each hurricane is different even if they have the same central pressure. Katrina and Camille were simular but different beasts. Looking back I'd rather have Camille hit here again than Katrina. I've seen the damage from both hurricanes and Katrina left Camille standing by the curb. Camille had stronger winds than Katrina but Katrina's water did way more damage than Camille. The SS scale was developed to show estimated damage potential a particular hurricane possesses.

From the NHC website:

Category Five Hurricane: Winds greater than 155 mph. Storm surge generally greater than 18 ft above normal. Complete roof failures on many residences and industrial buildings. Some complete buildings failures with small utility buildings blown over or away. All shrubs, trees, and signs blown down. complete destruction of mobile homes. Severe and extensive window and door damage. Low-lying escape routs are cut by rising water 3-5 hours before the arrival of the hurricane. Major damage to lower floors of all structures located less than 15 ft above sea level and within 500 yards of the shoreline.


Katrina met all of the above criteria except sustained winds. Other criteria was exceeded by a large margin. I have the pictures to prove the damage. Katrina made a joke of the SS scale and it needs to be revised......MGC

Yep! and I have a problem with that ALL Criteria was met ECEPT winds.... I mean if you have a storm that was a cat 5 and the winds drop to a cat 4 or even a cat 3 at landfall yet you STILL get a storm surge 25-35 feet and TOTAL destruction IMHO THATS a CAT 5! I guess what I'm saying is people focus too much onb the sustained winds when WATER (Surge) is a MUCH greater force...As I said before Living through SEVERAL storms I beleive Parts of South Mississippi Experienced CAT 4 SUSTAINED winds with gust into cat 5 and CAT 5 storm surge for MOST of the coast MS/LA Line over to Pascagoula...rivers Up to ten miles inland from Biloxi to escatawpa had water surged into them as high as 16 FEET Heck even Downtown MOBILE Nearly 100 miles East of the Center tied a record with 13 FEET of surge! Katrina was Much larger than Camille and push water in places till 8-29-05 had always been DRY~NO DOUBT in My mind KATRINA is now the Benchmark around here and Everywhere but some people who didnt ecxperience it or have seen the Destruction first hand ONLY look at Stats and its hard to understand why a CAT 4 did MORE damage than the Cat 5's did in Andrew and Camille....

[Ixolib]

ixolib....If I remeber correctly your just outside the base correct? Keesler had water in places it had NEVER reached. there was also some new buildings with severe roof damage. The map below shows approx where and how deep the water was (You may have already seen this?) I was sheltering just off Larcher Blvd about 3 blocks from the BX/Commissary which got 8-10 ft.! I have some wind damage photos somewhere on a disk

Hey rtd2 - you are correct. My back yard border's KAFB - I guess I'm about due north (or a tad NNE) of the main pool near gate 1, and the only thing seperating my property from the base is the perimiter fence. I guess that too puts me about three blocks from the BX/Commissary. I watched out my kitchen window as the base was overtaken by the surge - including Larcher Blvd!! Simply Amazing!! I think those buildings just south of me are part of the TLF facilities, right? Well, they're up even higher than I am and we watched as they all took on at least three feet!!

And you are right, they saw water there that had never been there before - just as I did here in my house. I've lived in this same house since 1963 and been through every storm since Betsy and NEVER did I see surge like this. In fact, even in Camille, the surge came nowhere close!! None-the-less, it is true that the winds in Katrina were significantly lesser than in Camille. But that is a moot point when one considers the end result. On the coast, the true killer and destructor in a landfalling hurricane is the surge. Perhaps wind becomes more of an issue the more inland one is...

I agree with MGC - the SS scale should be re-addressed, and the warnings given by the NHC ought to concentrate more on the surge potential than it does on the wind potential. The public has GOT to get better educated on the potential impacts of a storm like Katrina, and the winds easily take a back seat to the force of the water (perhaps except for a direct hit by one of the spawned tornadoes).

I'll take 140MPH sustained winds any day over storm surge in my home (been there - done that). The latter is easily more significant in the damage it does...

[Derek Ortt]

we need very strict criterion to determine the intensity of a TC and we have chosen wind. If we go on the damage, we may as well just use the F-scale

Katrina should have been a lesson for everyone. A cat 3 brings total devastation

[Ixolib]

we need very strict criterion to determine the intensity of a TC and we have chosen wind. If we go on the damage, we may as well just use the F-scale

Katrina should have been a lesson for everyone. A cat 3 brings total devastation

Yes, but a CAT 3 (or one that wasn't previously a CAT 5) hitting someplace that's lesser prone to surge will not produce the same results as one hitting somewhere that is more prone - like the northern gulf coast. If it wasn't for the surge of Katrina, the actual outcome would have been significantly reduced in terms of damage. Katrina's winds did NOT bring "total devastation". And actually, neither did her surge. Of the total number of homes in coastal Harrison County, the majority survived intact and are being lived in today - mine included.

I believe it's a safe bet to say that if surge had not been an extreme issue with Katrina, the news of her landfall and resulting impact would have lasted about a week or less...

[flhurricaneguy]

if a strom like katrina was to hit the east coast of florida, how much storm surge would we have to worry about? would it come miles inland?

[Derek Ortt]

east coast of Florida is not storm surge prone. heights on the Florida EC (except in bays) are very similar to surges in the eastern caribbean and Cayman.

In Broward, a cat 5 will only produce about 10 feet max. That said, you would just have 50 foot waves

[flhurricaneguy]

good to hear! i live about 4 miles inland in ST. Lucie county and i didnt think i had anything to worry about but just wanted to be sure

[terstorm1012]

http//www.aoml.noaa.gov/hrd/Landsea/landseabams2004.pdf


The Andrew reanalysis report, that explains where the Cat 5 winds were and the reason for the upgrade to Cat 5.

Pg 11 states that most of the county south of Kendall Drive (is that SW 88th Street or Avenue?) received Cat 3 and 4 conditions.

[Ixolib]

good to hear! i live about 4 miles inland in ST. Lucie county and i didnt think i had anything to worry about but just wanted to be sure.

Careful, don't let those words come back to haunt you......

[Tampa Bay Hurricane]

too bad the waters are shallow off Tampa Bay that means
higher surge-
We get storm surge even during strong thunderstorms that
come in off the gulf- a strong squall line pushed the water up
6 feet during a February 1998 storm...
thank God no Hurricanes have created big surges
or I would be homeless right now