new ivan landfall info... no cat 4

[Stratosphere747]

I think everyone is getting to focused on the category of the storm..Saying it "HAS" to be a Cat3 or 4 is not what Derek is trying to get across.. Each storm and the structure is has can make what may be a Cat3's damage less than what some Cat2's end up doing...

[Opal storm]

Ivan's winds at landfall were Cat3 strength.I think the thing is is that these people saying this was not a 3 did not witness the storm let alone got to the area hit by the storm.They just look at some pictures and read some wind devices and that's about it.If you had actually gone to Pensacola and looked at the devastation yourself you would have greater respect for what your talking about.If anybody told me Charley was a 2 I would laugh becuase I was there that night when Charley hit and I know for a fact that Charley was a 4.Just like the people in Pensacola,they witnessed Ivan and they know Ivan was nothing less than a 3.Ivan was not just a water storm,many buildings away from the water were destroyed by the wind.Those people up there aren't idiots,they've been through hurricanes before,and they will tell you Ivan was no 2.

[iceangel]

Ivan's winds at landfall were Cat3 strength.I think the thing is is that these people saying this was not a 3 did not witness the storm let alone got to the area hit by the storm.They just look at some pictures and read some wind devices and that's about it.If you had actually gone to Pensacola and looked at the devastation yourself you would have greater respect for what your talking about.If anybody told me Charley was a 2 I would laugh becuase I was there that night when Charley hit and I know for a fact that Charley was a 4.Just like the people in Pensacola,they witnessed Ivan and they know Ivan was nothing less than a 3.Ivan was not just a water storm,many buildings away from the water were destroyed by the wind.Those people up there aren't idiots,they've been through hurricanes before,and they will tell you Ivan was no 2.

THANK YOU, THANK YOU, THANK YOU!! You hit the nail on the head!!

[vbhoutex]

Mikey MIke and Opal Storm THANK YOU for EXCELLENT POSTS!!!!

[Derek Ortt]

opal storm,

you are still unable to make a post based upon science, instead, the method of rectal extraction is being used. No data says this was a cat 4 or a strong 3. Marginal 3? That is a different story. But to say this was anything like Charley is quite honestly, a clueless statement and shows how little one understands about the differences between wind and water damage


education needs to be made that a strong 2/weak 3 can cause billions of dollars worth of damage, not that Ivan was a strong 3 or a 4 and this is as bad as it gets

[Sanibel]

This controversy has made my local paper. It is important to determine the category because structural code improvements and hurricane science are furthered according to the findings.


I have to go with empirical science and Derek and agree that wind-measuring instruments that were in the same places as those claiming it was a category 3 only measured 89mph. I think some people are forgetting that if there were category 3 winds there 89mph sustained would be too weak to support them...


.

[Opal storm]

This is starting to sound like a presidential debate

I'm just going to have to agree to disagree since (according to you)I'm not good at science LOL.

[Aslkahuna]

I think we are focussing too much on the sustained winds. As the wind field of a hurricane (or ANY storm for that matter) comes ashore, friction quickly slows down the sustained winds. However, the GUSTS remain high and it's the high energy gusts that cause the spectacular damage to buildings softened up by a long period of lower sustained winds. Studies by JTWC showed that while the gust ratio to sustained overwater was 1.25, the ratio was more like 1.5-1.6 for winds overland. For a 90 mph sustained wind overland the gusts would be in the 135-144mph range which are the gusts one would expect from a 110-120 mph sustained wind overwater. At the top end of Category 2-110mph, these gusts along and just inland from the immediate shoreline could easily exceed 150 mph and anyone who has ever watched Jim Leonard's video of Typhoon Omar on Guam knows what a sudden high velocity gust can do to a structure.

Steve

[DoctorHurricane2003]

Derek I greatly disagree with you and your "attack" (rectal extraction) at Opal storm's beliefs.

First off, I hate to tell you, but Opal did not make landfall in Walton County. Opal made landfall very close to Navarre Beach. However, most major hurricane force winds were on the east side of the storm. This is why Gulf Breeze received Hurricane Erin-type winds and Pensacola just near that. Also, the most extensive storm surge was located at Pensacola and Navarre Beaches, as well as Okaloosa Island. Not between Destin and Panama City. Highest winds were in the general area of Hurlburt Field, Mary Esther, and Fort Walton Beach, which were clear signs of category 3 strength.

Secondly, your characterization of "wind" and "water" storms should quickly be put to a stop. While it is POSSIBLE for storms to be mostly water damage (like Opal) and mostly wind damage (like Erin) it is also, but more likely for storms to cause both wind and water damage (Charley and Ivan). Charley had done tremendous water damage to Captiva Island and portions of Northern Sanibel, while doing extreme wind damage around Punta Gorda, Port Charlotte, and moderate to minimal damage around Fort Myers and Orlando. Ivan, on the other hand, did major water damage to Perdido Key and Santa Rosa Island, as well as a portion of Okaloosa Island. However, most structural building failures in the Pensacola area were due to wind damage (IE, Crowne Plaza Hotel and Amsouth Bank-Gulf Breeze).

Thirdly, we must also not forget that the northern eyewall of Ivan had decomposed before landfall, but the Eastern eyewall that raked over western Pensacola was still quite intact. Also, Ivan was larger than most previous storms, allowing for a large expanse of Hurricane force winds. Because instruments fail and sometimes (example: Pensacola Regional Airport Sensor) do not properly read high wind speeds, as well as the fact that the category 3 winds most likely did not catch a properly working sensor.....I would think that winds were near 125-130 MPH at landfall. It only makes sense when you look at and compare damage to previous storms. The average wind damage in the Pensacola area, for example, does not properly match that of Hurricane Georges in 1998 (Category 2 110 MPH), but is most definitely more extensive/severe. It also appears more extensive/severe than Hurricane Fran in 1996 (Category 3 115 MPH).

It is not proper to compare this to storms prior to 1995 due to updated building code standards....and certainly isn't proper to compare to 1979-Frederic (Building Codes Substandard Today) and 1969-Camille (Very strong).

[Opal storm]

Derek I greatly disagree with you and your "attack" (rectal extraction) at Opal storm's beliefs.

First off, I hate to tell you, but Opal did not make landfall in Walton County. Opal made landfall very close to Navarre Beach. However, most major hurricane force winds were on the east side of the storm. This is why Gulf Breeze received Hurricane Erin-type winds and Pensacola just near that. Also, the most extensive storm surge was located at Pensacola and Navarre Beaches, as well as Okaloosa Island. Not between Destin and Panama City. Highest winds were in the general area of Hurlburt Field, Mary Esther, and Fort Walton Beach, which were clear signs of category 3 strength.

Secondly, your characterization of "wind" and "water" storms should quickly be put to a stop. While it is POSSIBLE for storms to be mostly water damage (like Opal) and mostly wind damage (like Erin) it is also, but more likely for storms to cause both wind and water damage (Charley and Ivan). Charley had done tremendous water damage to Captiva Island and portions of Northern Sanibel, while doing extreme wind damage around Punta Gorda, Port Charlotte, and moderate to minimal damage around Fort Myers and Orlando. Ivan, on the other hand, did major water damage to Perdido Key and Santa Rosa Island, as well as a portion of Okaloosa Island. However, most structural building failures in the Pensacola area were due to wind damage (IE, Crowne Plaza Hotel and Amsouth Bank-Gulf Breeze).

Thirdly, we must also not forget that the northern eyewall of Ivan had decomposed before landfall, but the Eastern eyewall that raked over western Pensacola was still quite intact. Also, Ivan was larger than most previous storms, allowing for a large expanse of Hurricane force winds. Because instruments fail and sometimes (example: Pensacola Regional Airport Sensor) do not properly read high wind speeds, as well as the fact that the category 3 winds most likely did not catch a properly working sensor.....I would think that winds were near 125-130 MPH at landfall. It only makes sense when you look at and compare damage to previous storms. The average wind damage in the Pensacola area, for example, does not properly match that of Hurricane Georges in 1998 (Category 2 110 MPH), but is most definitely more extensive/severe. It also appears more extensive/severe than Hurricane Fran in 1996 (Category 3 115 MPH).

It is not proper to compare this to storms prior to 1995 due to updated building code standards....and certainly isn't proper to compare to 1979-Frederic (Building Codes Substandard Today) and 1969-Camille (Very strong).

Thanks Doctor Hurricane,great post!

[Derek Ortt]

http://www.nhc.noaa.gov/1995opal.html

read this report. Dopple radar data clearly stated that the highest winds were bwteen Destin and Panama City, well east of the eye. Pensacola didnt even come close to the strongest winds, neither did the other areas you mentioned. I have also read reports that the 144 gust was an error, which is consistent with the recon data. With Ivan, the RMW was very near Pensacola. You can accept what you believe, or you can go with the accepted science. If there is an error, I'd love to see a scientific report on the matter, or for you to contact the Hurricane research Division of NOAA to have this changed since they are conducting a re-analysis

Asklahauna, good point about the difference between sustained winds and gusts. However, where the 89 m.p.h. sustained was recorded, the maximum gust was only 115 m.p.h. I do not contest that there were higher gusts to the east by about 50NM, because there were. However, when the stations started to fail in both Georges and Ivan, the wind readings were remarkably similar, about 125 m.p.h. in gusts. We need some better observation posts in the part of the USA.

Also, of note: the 700mb winds in both Opal and Ivan are remarkably similar and Opal was nowhere near a cat 4 at landfall.

[MGC]

Rating Ivan's intensity based on one instrument measuring 89mph in a hurricane of Ivan's size is like looking at your toe and diagnosing a disease elsewhere in the body. Didn't all the wind measuring equipment fail in Pensacola well before Ivan's real wind field hit? Using doppler to estimate surface winds at that distance is suspect at best. Inland wind damage looked way beyond 89mph.......MGC

[Opal storm]

Rating Ivan's intensity based on one instrument measuring 89mph in a hurricane of Ivan's size is like looking at your toe and diagnosing a disease elsewhere in the body. Didn't all the wind measuring equipment fail in Pensacola well before Ivan's real wind field hit? Using doppler to estimate surface winds at that distance is suspect at best. Inland wind damage looked way beyond 89mph.......MGC

The 89mph wind thing is a joke,and yes all the wind devices failed just after Ivan's landfall.Those devices were made to survive winds of 120mph.

[Derek Ortt]

also lets not forget the wind analysis map I had posted earlier based upon microwave data from the recon aircraft. That analysis yielded 95KT maximum winds at landfall. a 95KT hurricane will still cause very serious damage

[Brent]

Well... let's look at the Saffir-Simpson scale:

Category Two Hurricane:
Winds 96-110 mph (83-95 kt or 154-177 km/hr). Storm surge generally 6-8 feet above normal. Some roofing material, door, and window damage of buildings. Considerable damage to shrubbery and trees with some trees blown down. Considerable damage to mobile homes, poorly constructed signs, and piers. Coastal and low-lying escape routes flood 2-4 hours before arrival of the hurricane center. Small craft in unprotected anchorages break moorings. Hurricane Bonnie of 1998 was a Category Two hurricane when it hit the North Carolina coast, while Hurricane Georges of 1998 was a Category Two Hurricane when it hit the Florida Keys and the Mississippi Gulf Coast.

Category Three Hurricane:
Winds 111-130 mph (96-113 kt or 178-209 km/hr). Storm surge generally 9-12 ft above normal. Some structural damage to small residences and utility buildings with a minor amount of curtainwall failures. Damage to shrubbery and trees with foliage blown off trees and large trees blown down. Mobile homes and poorly constructed signs are destroyed. Low-lying escape routes are cut by rising water 3-5 hours before arrival of the center of the hurricane. Flooding near the coast destroys smaller structures with larger structures damaged by battering from floating debris. Terrain continuously lower than 5 ft above mean sea level may be flooded inland 8 miles (13 km) or more. Evacuation of low-lying residences with several blocks of the shoreline may be required. Hurricanes Roxanne of 1995 and Fran of 1996 were Category Three hurricanes at landfall on the Yucatan Peninsula of Mexico and in North Carolina, respectively.

Category Four Hurricane:
Winds 131-155 mph (114-135 kt or 210-249 km/hr). Storm surge generally 13-18 ft above normal. More extensive curtainwall failures with some complete roof structure failures on small residences. Shrubs, trees, and all signs are blown down. Complete destruction of mobile homes. Extensive damage to doors and windows. Low-lying escape routes may be cut by rising water 3-5 hours before arrival of the center of the hurricane. Major damage to lower floors of structures near the shore. Terrain lower than 10 ft above sea level may be flooded requiring massive evacuation of residential areas as far inland as 6 miles (10 km). Hurricane Luis of 1995 was a Category Four hurricane while moving over the Leeward Islands. Hurricanes Felix and Opal of 1995 also reached Category Four status at peak intensity.

You be the judge. I've seen hundreds of pictures from the area.

[DoctorHurricane2003]

Official Sensors along the coast in Santa Rosa, Okaloosa, and Walton Counties are basically non-existant with the exception of Hurlburt Field...but they are well inland. Let's not forget that Doppler Radar at those distances (medium range) aren't very good 100% of the time (Example: Hurricane Jeanne 179 KT estimate in the hours before landfall).

It is better to say "we won't know, but probably...," however the damage related to wind in the areas to the east of Opal's eye were Category 3-rated (I'm sorry you did not live here).

I also think its quite funny that you chose to only respond to my first point, and not my second or thirds. But that can live to another day.

[DoctorHurricane2003]

95 KT damage is not as serious as the damage here, IMO. (Georges vs. Ivan)

The microwave data sometimes may not represent facts correctly, especially when you have the unraveling hurricanes such as Ivan. Ground movements and tornadoes may also effect the outcomes of microwave data.

[Derek Ortt]

In Opal, not only did the doppler radar show the winds between Destin and Panama City, but the recon showed the same thing. I will trust recon data over a surface ob that has been discredited

also, eye witness reports, to be honest, often are unreliable,e specially when it comes to wind estimates. The general public almost always overestimates the wind speeds. Hell, I also do that and I know better

third, you will NEVER see a hurricane classified based upon damage. I know for a fact that best track will not indicate a strong category three hurricane and the hurricane came in between data points. Let me just put it this way, its weaker than was operationally indicated and NHC said as much in their report, they were hinting 100-105KT, which is much weaker than some are caliming here in this thread.

The SS Scale is not absolute and to be honest, those descriptions are laughable as they only apply to the Miami area, especially the storm surge heights. Thankfully, those in the field know that a strong 2 to weak 3 produces about 12-15 feet of surge in the GOM

I will repeat this again, even though I will be wasting my time typing, Pensacola got their strongest winds form Ivan (roughly strong cat 1 to weak cat 2) since the 1926 hurricane.

If someone can come up with surface obs that have been verified and not personal inflated wind estimates

[DoctorHurricane2003]

So, based on your opinion....if Camille had come in between data points and the highest measured surface ob was 120 MPH, and the recon microwave data showed winds in the 125 KT range....you would say that Camille would have been a category 4 despite apparent wind and water damage?

Let us not forget what happened with Andrew....everyone thought Category 4.....then the extreme damage as well as a few surface obs that were unofficial at that time led people to question what it was.

[Opal storm]

In Opal, not only did the doppler radar show the winds between Destin and Panama City, but the recon showed the same thing. I will trust recon data over a surface ob that has been discredited

also, eye witness reports, to be honest, often are unreliable,e specially when it comes to wind estimates. The general public almost always overestimates the wind speeds. Hell, I also do that and I know better

third, you will NEVER see a hurricane classified based upon damage. I know for a fact that best track will not indicate a strong category three hurricane and the hurricane came in between data points. Let me just put it this way, its weaker than was operationally indicated and NHC said as much in their report, they were hinting 100-105KT, which is much weaker than some are caliming here in this thread.

The SS Scale is not absolute and to be honest, those descriptions are laughable as they only apply to the Miami area, especially the storm surge heights. Thankfully, those in the field know that a strong 2 to weak 3 produces about 12-15 feet of surge in the GOM

I will repeat this again, even though I will be wasting my time typing, Pensacola got their strongest winds form Ivan (roughly strong cat 1 to weak cat 2) since the 1926 hurricane.

If someone can come up with surface obs that have been verified and not personal inflated wind estimates

Strong cat 1 to weak cat 2 winds is false and everyone knows it.