Enhanced Fujita Ratings Debate Thread

Lori

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#1
https://en.wikipedia.org/wiki/Enhanced_Fujita_scale

Please be respectful and mature, obey forum rules but it was brought up in the damage report for this last severe wx event and I think we had a big discussion on TW before the forum crash. I'd like to see some examples of what you think were too conservative of ratings and why. Again, no fussing, if there is a disagreement, please do it respectfully!

I have no proof or backing but I really feel like the Tuscaloosa tornado was very, very close to being an EF-5....I'm curious as to why the rating wasn't higher than an EF-4, remind me, was it a high end EF-4? I didn't see much of a difference between the damage that occurred in Hackleburg than I saw in Tuscaloosa and I saw both in person.

Okay....let's debate and talk about this!!

Be sweet y'all!!
 

Kory

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#3
Agreed with that Lori. I saw the damage out by Hurricane Creek and Alberta City/Holt region from the Tuscaloosa tornado. That steel train trestle that passed over Hurricane Crek was completely mangled. There was an apartment complex out in Holt, I believe they were called Chastain Manor. Fairly well built (supposedly) that was completely just leveled. Apparently they weren't properly anchored, but I wasn't there so I can't comment on that. As far as the steel trestle....I can't imagine what type of force it takes to completely mangle and throw pieces hundreds of yards.
 

PerryW

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#5
Lori, it is generally very difficult to accurately tell the difference between EF4 and EF5 wind speeds. because once winds exceed 170 mph......most structures, and all vehicles, trailers, etc will be destroyed. .
 
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#6
Vilonia, Chickasha, and Goldsby will still always be the 3 most obvious EF5s that we're errounously rated EF4. Vilonia irks me the most, especially given how the lead surveyor verbaly communicated his incredibly biased interpretation of the EF scale after the event, which was basically a sugar coated version of "I don't believe in EF5 house damage." Not to mention The historical significance of it being the first clear cut instance of EF5 damage in Arkansas state history, yet it wasn't rated as such. Frustrating.

I feel like one could argue a case for Rochelle-Fairdale as well as Abeline-Chapman too, but those are a little more borderline.

As far as Tuscaloosa, I may be in the minority here, but I feel that high-end EF4 is technically the correct rating. At the end of the day, no well-built and anchor bolted homes were swept away by that tornado, and Chastain Manor was nailed directly into a concrete slab, which is honestly terrible construction for such a large building. Given, the damage to the railroad trestle was extremely impressive. So was the Tuscaloosa tornado an EF5? Almost certainly. Did it produce any legitimate, clear-cut EF5 damage? It did not. Kind of a good example of how the scale is not perfect.
 
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#8
The more I hear about Flat Rock and Cullman from 4/27 over time, the more I think they were likely EF5's at some point or another. Apparently there was a large cinderblock house near Baileyton on the Cullman track that was completely leveled and had multiple fatalities, and a UAH researcher who saw the damage firsthand believes it was a 5 in that area when supported with contextual evidence IIRC. While I don't have any pictures of this, for those of y'all who know CAL, he's told me that the tree damage he saw in rural areas outside Flat Rock on 4/27 was simply phenomenal and by far the worst he's ever seen. However it didn't hit any structures at this point so there's no real way to justify an EF5 without using tree damage.
 
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#9
I'm sure that several of the EF4s on 27 April were capable of EF5 damage at some point. Had they hit structures of appropriate strength, I'm sure Tuscaloosa, Ringgold, Cullman/Arab, possibly Jasper, maybe even a couple of others were all capable of EF5 damage at some point in their lives.
 
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#10
I believe the Tuscaloosa tornado was an ef 5 at some point. I saw complete slabs of foundation in some pictures in the past. The Cordova tornado as well had to be an EF5 at some point. The Cullman tornado, I would agree with ef4 damage but not in the city. In the city it looked more like an ef3. I was in downtown 15 minutes after the tornado hit, and it looked bad, but not like Tuscaloosa.
 
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#11
The EF scale damage is determined by humans, so there will always be a margin of error due to the subjective nature of human interpretation. Quantification of storm strength by damage analysis alone is error prone due to variances in structural strengths/weaknesses, etc. We need better tools to measure the strength of the storm itself rather than damage signatures.
 
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#12
Vilonia, Chickasha, and Goldsby will still always be the 3 most obvious EF5s that we're errounously rated EF4. Vilonia irks me the most, especially given how the lead surveyor verbaly communicated his incredibly biased interpretation of the EF scale after the event, which was basically a sugar coated version of "I don't believe in EF5 house damage." Not to mention The historical significance of it being the first clear cut instance of EF5 damage in Arkansas state history, yet it wasn't rated as such. Frustrating.

I feel like one could argue a case for Rochelle-Fairdale as well as Abeline-Chapman too, but those are a little more borderline.

As far as Tuscaloosa, I may be in the minority here, but I feel that high-end EF4 is technically the correct rating. At the end of the day, no well-built and anchor bolted homes were swept away by that tornado, and Chastain Manor was nailed directly into a concrete slab, which is honestly terrible construction for such a large building. Given, the damage to the railroad trestle was extremely impressive. So was the Tuscaloosa tornado an EF5? Almost certainly. Did it produce any legitimate, clear-cut EF5 damage? It did not. Kind of a good example of how the scale is not perfect.
Vilonia, Chickasha, and Goldsby will still always be the 3 most obvious EF5s that we're errounously rated EF4. Vilonia irks me the most, especially given how the lead surveyor verbaly communicated his incredibly biased interpretation of the EF scale after the event, which was basically a sugar coated version of "I don't believe in EF5 house damage." Not to mention The historical significance of it being the first clear cut instance of EF5 damage in Arkansas state history, yet it wasn't rated as such. Frustrating.

I feel like one could argue a case for Rochelle-Fairdale as well as Abeline-Chapman too, but those are a little more borderline.

As far as Tuscaloosa, I may be in the minority here, but I feel that high-end EF4 is technically the correct rating. At the end of the day, no well-built and anchor bolted homes were swept away by that tornado, and Chastain Manor was nailed directly into a concrete slab, which is honestly terrible construction for such a large building. Given, the damage to the railroad trestle was extremely impressive. So was the Tuscaloosa tornado an EF5? Almost certainly. Did it produce any legitimate, clear-cut EF5 damage? It did not. Kind of a good example of how the scale is not perfect.
 
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#13
Don't forget this and it was far past the tornado's peak.
As the tornado moved across a coal yard in this area, a 35.8-tonne (78,925 lb) coal car was thrown 391 ft (119 m) though the air.
To me, when watching the tornado track video, the 70 or so miles of timber completely flattened in a mile wide swath is more indicative of an EF5 than a tornado that briefly causes a thousand feet of "EF5" damage. Only the strongest of strong tornadoes can pack that kind of wallup for that many miles. The fact that the Hackle-Campbell did that for 132 miles is incomprehensible.

They gave the Joplin tornado an EF5 rating based on the amount of damage which it did a lot of but it didn't do 80 miles of destruction.

JOPLIN, Mo. — A new engineering study of the damage caused by the May 2011 tornado that struck Joplin found no evidence that it was an EF5, as the National Weather Service found, because the city's homes and businesses weren't built to withstand wind speeds that strong, making such a determination impossible.

(MORE: Magnets for Disaster?)

The study by the American Society of Civil Engineers found that more than 83 percent of the damage on May 22, 2011, was caused by winds of 135 mph or less, which is equal to the maximum wind speed of an EF2 tornado, and that about 13 percent of the damage was caused by winds of 138-167 mph, consistent with an EF3 tornado. Only 4 percent of the damage was indicative that it had been an EF4 tornado, which can have winds speeds ranging from 168 to 199 mph, the report said.

The ASCE team also found that while the tornado's maximum wind speed was around 200 mph, there was no evidence of building damage from winds at 200 mph or greater, the minimum threshold for an EF5. The ASCE investigators concluded it was impossible to find evidence of E-5 ratings in the damage because none of the buildings met the high construction quality threshold required for determining that level of wind speed, The Joplin Globe reported Saturday.


The findings of the ASCE damage-assessment team are based on five days of surveying damage in more than 150 buildings in a six-mile segment of the tornado's Joplin path. The total tornado path was 22 miles. More than 7,000 structures were destroyed or badly damaged by the tornado, and 161 people were killed.

The ASCE findings, however, do not change the National Weather Service's classification of the Joplin tornado as an EF5, with peak winds of 200-208 mph.
 
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#14
The more I hear about Flat Rock and Cullman from 4/27 over time, the more I think they were likely EF5's at some point or another. Apparently there was a large cinderblock house near Baileyton on the Cullman track that was completely leveled and had multiple fatalities, and a UAH researcher who saw the damage firsthand believes it was a 5 in that area when supported with contextual evidence IIRC. While I don't have any pictures of this, for those of y'all who know CAL, he's told me that the tree damage he saw in rural areas outside Flat Rock on 4/27 was simply phenomenal and by far the worst he's ever seen. However it didn't hit any structures at this point so there's no real way to justify an EF5 without using tree damage.
Cullman County only had 2 fatalities on April 27, 2011. One occurred in Johnson's Crossing near Hanceville in the early-morning storms. The other occurred either in or near the city of Cullman with the EF-4 tornado. There were not multiple fatalities near Baileyton in Cullman County.

Edit to add...I drove all the way to Smith Lake to where the tornado first started doing significant damage in the county and followed the track. The strongest damage, IMO, was when the tornado destroyed homes, businesses and churches in the area of Hwy 278 East. But even that was not indicative of EF-5 damage. Interesting fact...as long as records have been kept, Cullman County has never had (or at least determined to be) an F-5/EF-5 tornado.
 

Lori

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#15
The EF scale damage is determined by humans, so there will always be a margin of error due to the subjective nature of human interpretation. Quantification of storm strength by damage analysis alone is error prone due to variances in structural strengths/weaknesses, etc. We need better tools to measure the strength of the storm itself rather than damage signatures.
Exactly!!
 
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#16
The one around these parts that was messed up was the April 2 2006. It was rated an EF3 and was clearly EF4 imo. I watched it from a couple miles away and helped in the aftermath. There was 26 fatalities total with 13 in our county in a 4 to 5 mile stretch. I remember one house in particular that was completely gone except for slab with bolts sheared off. In the grand scheme it does not matter but it has always bothered me.
 
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#17
The one around these parts that was messed up was the April 2 2006. It was rated an EF3 and was clearly EF4 imo. I watched it from a couple miles away and helped in the aftermath. There was 26 fatalities total with 13 in our county in a 4 to 5 mile stretch. I remember one house in particular that was completely gone except for slab with bolts sheared off. In the grand scheme it does not matter but it has always bothered me.
2006 was right before things switched over to the EF scale, and the ratings during that time period were extremely low-balled, as I believe surveyors were at a loss as to how to apply a scale that desperately needed an update. F3 seemed to be the ceiling of the scale during that time (the violent Westminster, TX tornado produced very high-end damage that year and was rated F3).

And you saw sheared off bolts? Wow!
 
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#18
There was 1 officially rated F4 in 2005 and two in 2006. Not completely ridiculous given those were fairly lean years for tornado activity coupled with the overall rarity of violent tornadoes, but it does seem like the scale was applied quite conservatively in those two years. Caruthersville and Newbern from April 2 and Westminster were all legit F4 candidates IMO. The Stoughton, WI tornado of 18 August 2005 (which just missed my house) was considered for F4 but they ultimately went with high-end F3 which I think was a good, if conservative rating. Could have gone F4 but there was no blatant F4 damage that was missed/ignored. There were some houses that were completely collapsed down to piles of debris but their build quality was suspect. Some unanchored houses blew off their foundations and disintegrated, which could be called F5 damage if you didn't look carefully. The well-built houses in the worst damaged areas generally had textbook F3 damage, with only 1st floor interior walls standing. Vehicles were moved/flipped but not thrown long distances and mangled.
 
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PerryW

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#19
The one around these parts that was messed up was the April 2 2006. It was rated an EF3 and was clearly EF4 imo. I watched it from a couple miles away and helped in the aftermath. There was 26 fatalities total with 13 in our county in a 4 to 5 mile stretch. I remember one house in particular that was completely gone except for slab with bolts sheared off. In the grand scheme it does not matter but it has always bothered me.
Agree.....IMO that was clearly a F4 tornado; in fact, both the Caruthersville MO and Newbern TN should have been rated F4's.
 
#20
Another thing to consider is that 2006 was still feeling the effects of "La Plata syndrome" to a point. After that blunder ratings became highly conservative for a few years, almost like the NWS was embarrassed over it. I'm also not sure why there's so much of a controversy around the La Plata tornado's rating at all. It was an honest mistake from an inexperienced survey team, and obviously the rating downgrade wasn't a personal insult to the victims.
 

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