Enhanced Fujita Ratings Debate Thread

[CheeselandSkies]

A key breakpoint exists between how the legacy Fujita (F) scale and the EF scale handle the complete
destruction and sweeping away of single-family homes, with standard “well-constructed” homes
being swept away constituting F5 damage on the F scale but only EF4 damage on the EF scale.

I'm glad someone official finally admitted this. When the EF-scale was being adopted, I recall being told in multiple publications that the scales were intended to be applied in the same way (what was rated F5 before, should be rated EF5 now and so on down the scale); just that the new scale with its detailed DIs would provide some specificity to the rather vague and subjective damage descriptors in the old scale, thus giving surveyors more confidence and alleviating the "La Plata syndrome" which had become rampant.

It was a lie.

However, it's refreshing to see some in the "official" tornado research community finally taking a serious look at this. Perhaps it's been going on too long, and starting to creep down the scale as well (such that the determination between EF3 and EF4 has in some cases become as controversial as EF4-EF5 was not too long ago) that it can no longer be dismissed as Twitter weenies wanting every tornado to be rated higher.

 

[NewFoundWeatherNerd]

I felt I could provide a little added information to this thread surrounding the ratings of NWS Fort Worth specifically; Ive spoken to them "extensively" in my time attending Storm Spotter trainings.
They have 27 total employees, only a few of which can officially work on damage surveying; and they're often short staffed in the spring due to the need for forecasters.

Latest information I know with surveys:
-It took around 2-weeks in total to survey the 5/25/24 event; with two teams being deployed over two days after the tornadoes. These teams consisted of three people in total, so one team consisted of two people, while Jennifer Dunn made up the second team.
-This was due to there still being active weather to monitor outside the prior day, into the 26th and 27th.
-For Valley View, they got the assistance of outside sources to help finalize the rating, potentially Tim Marshall but I cannot confirm that with certainty. One of the EF3s was actually originally rated EF2, before being upgraded due to said outside consolation.
-The last time NWS Fort Worth utilized an aerial survey was with the Granbury EF4; in which a plane was used.
-They are actively looking into using satellites and drones to help with tornado damage surveys
-NWS Fort Worth does NOT currently use the new EF-Scale in development; in their words: "We're waiting on further progress and for the people above us on that to confirm things".

I hope this clears some things up surrounding their office in particular; they are wonderful people to speak to, and are working hard on fixing things up. If anyone wants clarity on stuff, feel free to ask me; I heard all of this at the Collin and Parker County Spotter Trainings.

 

[Sawmaster]

Thank you for sharing that. Lack of staffing is always a problem and will likely become severe if current political directions prevail. One of the things which exacerbates the problem is "waiting on further progress and for the people above us on that to confirm things".. As long as it isn't carried to extremes surveyors could decide to 'favor' higher ratings where they think appropriate but everyone seems scared to take that step. Nothing ever changes till someone becomes the first to do it.

Very glad you seem to have good and competent people at your local NWS; that isn't the case everywhere.

 

[NewFoundWeatherNerd]

Thank you for sharing that. Lack of staffing is always a problem and will likely become severe if current political directions prevail. One of the things which exacerbates the problem is "waiting on further progress and for the people above us on that to confirm things".. As long as it isn't carried to extremes surveyors could decide to 'favor' higher ratings where they think appropriate but everyone seems scared to take that step. Nothing ever changes till someone becomes the first to do it.

Very glad you seem to have good and competent people at your local NWS; that isn't the case everywhere.

Basically; they may not have any tornado within recent memory within the NWS FWD space to use the new scale for (not yet anyway). Valley View didnt really fit into a place where special things had to be done; it did not produce conventual violent damage. I even went to the damage area in August last year, there was impressive damage indeed; but nothing stood out as inherently violent; although, dont get me wrong, the tree damage was impressive.

If something where to occur within their CWA which required special examination; I do wonder deeply what their steps would be. They mentioned something about looking for help with more extensive, hard to reach, or widespread damage from tornadoes; so I would say to watch for that if something bad does occur. Specifically with drones actually. I do look to be of assistance to NWS Fort Worth in the situation we see violent tornado damage; and if that happens Ill update everyone here on what it's like.

In which, if there's an office within recent time to trust, its NWS FWD; they recently completely redid their armature radio system and seem to genuinely be wanting to clarify things to those interested in them. Ill update on any sort of information I have with ratings if I find out

 

[Sawmaster]

Thanks for the elucidation. Hey, I gotta use big words now and then
Our local Ham skywarn op is pretty dead as the MWS office manager has stated their main focus is on social media. Oh well, their choice. The guy I handed it off to rather screwed things up and I'm done with it now. TOR warnings here are "Plainfield syndrome" personified and magnified, with well under 5% accuracy so nobody pays attention to them anymore. Anything stronger than a fart gets a radar TOR here. Maybe acceptable since we rarely see even a high EF-1 adn non-tornadic winds do a whole lot more damage. They'd never make it where you are. I do like good news wherever it happens so looking forward to whateber you can sgare with us from your neck of the woods (or plains as the case may be)

 

[slenker]

Thanks for the elucidation. Hey, I gotta use big words now and then
Our local Ham skywarn op is pretty dead as the MWS office manager has stated their main focus is on social media. Oh well, their choice. The guy I handed it off to rather screwed things up and I'm done with it now. TOR warnings here are "Plainfield syndrome" personified and magnified, with well under 5% accuracy so nobody pays attention to them anymore. Anything stronger than a fart gets a radar TOR here. Maybe acceptable since we rarely see even a high EF-1 adn non-tornadic winds do a whole lot more damage. They'd never make it where you are. I do like good news wherever it happens so looking forward to whateber you can sgare with us from your neck of the woods (or plains as the case may be)

Most of my own family is unfortunately a victim of the "cry-wolf" effect that radar-warned tornado warnings have caused, just because I live in central Ohio. Outside of the 70's and 80's we haven't had (please correct me if I'm wrong) any violent tornadoes here, even though it is absolutely possible given the correct meteorological setup. So when a tornado warning occurs, a portion of my family would rather gawk at the TV and go look outside rather than seeking shelter, because they "never happen here," and "it's an Oklahoma thing!" which really annoys me.

 

[joshoctober16]

Most of my own family is unfortunately a victim of the "cry-wolf" effect that radar-warned tornado warnings have caused, just because I live in central Ohio. Outside of the 70's and 80's we haven't had (please correct me if I'm wrong) any violent tornadoes here, even though it is absolutely possible given the correct meteorological setup. So when a tornado warning occurs, a portion of my family would rather gawk at the TV and go look outside rather than seeking shelter, because they "never happen here," and "it's an Oklahoma thing!" which really annoys me.

isn't that the mindset people in Rainsville Alabama had? and then you know... the EF5 hit.

 

[NewFoundWeatherNerd]

Thanks for the elucidation. Hey, I gotta use big words now and then
Our local Ham skywarn op is pretty dead as the MWS office manager has stated their main focus is on social media. Oh well, their choice. The guy I handed it off to rather screwed things up and I'm done with it now. TOR warnings here are "Plainfield syndrome" personified and magnified, with well under 5% accuracy so nobody pays attention to them anymore. Anything stronger than a fart gets a radar TOR here. Maybe acceptable since we rarely see even a high EF-1 adn non-tornadic winds do a whole lot more damage. They'd never make it where you are. I do like good news wherever it happens so looking forward to whateber you can sgare with us from your neck of the woods (or plains as the case may be)

Hah! I just genuinely like big words lol; fun to write!
But seriosly, im very sorry your office has what seems to be little experience with tornado warnings; that can go very wrong if something unusually strong were to occur. Goes to show how important radar and basic training can be; I worry that might go into rating them too!

 

[andyhb]

A paper that everyone here needs to read if you're interested in this topic: https://journals.ametsoc.org/view/j...D-24-0066.1/BAMS-D-24-0066.1.xml?tab_body=pdf

A key breakpoint exists between how the legacy Fujita (F) scale and the EF scale handle the complete
destruction and sweeping away of single-family homes, with standard “well-constructed” homes
being swept away constituting F5 damage on the F scale but only EF4 damage on the EF scale.
To illustrate this point, adjusting the lower-bound of EF5 on the EF scale from 201 mph to 190
mph or increasing all 190–200-mph EF4s to >200 mph EF5s to account for this breakpoint in the
handling of single-family homes would lead to consistent 5-level rating assignments from 1880
through present day.

The raw EF5 wind speed range described in WSEC (2006), which was derived from a linear regression relationship between the individual DI/DOD wind speeds determined through the “expert elicitation” process for the EF scale as a function of independent legacy F-scale wind speed estimations, was 200–234 mph. However, after this linear regression derivation, the committee rounded each wind speed range to 5-mph increments, with the rounding applied at the top of each range. Therefore, the raw 168–199-mph EF4 wind speed range was adjusted to 166–200 mph, which led to the starting threshold for EF5 being changed from 200 mph to 201 mph (WSEC 2006; their Table 6). Consequently, under the strictest application of the EF scale, to attain an EF5 rating from a single-family home being swept off its foundation, the home must technically be built above building code, which is a fundamental break from the F scale and will inherently reduce the number of EF5 DIs found in surveys.

I mean, good grief. Without this singular episode of incompetence, none of this constant argument/debate might exist.

 

[Brice W]

A paper that everyone here needs to read if you're interested in this topic: https://journals.ametsoc.org/view/j...D-24-0066.1/BAMS-D-24-0066.1.xml?tab_body=pdf




I mean, good grief. Without this singular episode of incompetence, none of this constant argument/debate might exist.

it’s always interested me why Rochelle wasn’t given an EF5 when it was literally one mph away from the threshold.

 

[slenker]

it’s always interested me why Rochelle wasn’t given an EF5 when it was literally one mph away from the threshold.

Not only was it rated a 200 mph EF4, it had over fifteen 200 mph damage indicators on the DAT, with some of them not even that close to the actual core of the damage path. It’s the reason why I dislike Rochelle being rated EF4 very strongly, the tornado was without a shadow of a doubt capable of EF5 damage and I believe it is entirely reasonable to upgrade it as such.

Also, after looking through the survey in the DAT, I found this funky little thing:

A 200 MPH EF3 damage indicator…? With a description that sounds extreme (although it doesn’t sound outside of the realm for HE EF4s, especially nowadays). Overall, very strange. I genuinely believe Rochelle was almost as bad of a snuff as some of the other infamous 190 - 200 mph EF4s.

 

[Brice W]

Not only was it rated a 200 mph EF4, it had over fifteen 200 mph damage indicators on the DAT, with some of them not even that close to the actual core of the damage path. It’s the reason why I dislike Rochelle being rated EF4 very strongly, the tornado was without a shadow of a doubt capable of EF5 damage and I believe it is entirely reasonable to upgrade it as such.

Also, after looking through the survey in the DAT, I found this funky little thing:
View attachment 34041
A 200 MPH EF3 damage indicator…? With a description that sounds extreme (although it doesn’t sound outside of the realm for HE EF4s, especially nowadays). Overall, very strange. I genuinely believe Rochelle was almost as bad of a snuff as some of the other infamous 190 - 200 mph EF4s.

You could make this a case for some of the 165’s we’ve had as well. Robinson and Dresden are a couple that come to my mind. I know we discussed this back in the 12/10/21 thread. Seems like the overall guidelines of the EF scale have been completely manipulated into what each National Weather Office simply wants. Some are very thorough and efficient with their surveys while some are missing DAT’s and simply don’t have an explanation why such was rated as. I guess an easier way of saying that is they are just simply lazy. Granted that some haven’t seen a true EF5 or F5 to truly get a grasp on how severe the damage needs to look in order to get the rating. But that shouldn’t be an issue when you know what to exactly look for. All of them needed schooling and needed to get qualified in some aspect to do what they do.

 

[Brice W]

This is just my personal opinion, feel free to chime in. But I feel like the only appropriate tornado to receive the “dreaded 190 rating” is Washington 2013. Obviously a violent tornado, I don’t remember seeing anything that looked like it was the in realm of EF5 damage unlike some of the other tornadoes before it? Correct me if I’m wrong, obviously Goldsby and Chickasha were two notorious storms that definitely should've gotten an EF5 rating.

 

[UK_EF4]

This is just my personal opinion, feel free to chime in. But I feel like the only appropriate tornado to receive the “dreaded 190 rating” is Washington 2013. Obviously a violent tornado, I don’t remember seeing anything that looked like it was the in realm of EF5 damage unlike some of the other tornadoes before it? Correct me if I’m wrong, obviously Goldsby and Chickasha were two notorious storms that definitely should've gotten an EF5 rating.

I also feel like Bassfield had in reality quite a fair rating. The damage to the home was very impressive but especially if it was impacted by a large truck and appears to just be connected along the perimeter of the foundation, I think high end EF4 was probably realistic. No doubt the tornado was of EF5 intensity especially with that tree damage just to the NE of this location, but I think the survey was thorough, well done, and the scale was applied accurately.

 

[UK_EF4]

You could make this a case for some of the 165’s we’ve had as well. Robinson and Dresden are a couple that come to my mind. I know we discussed this back in the 12/10/21 thread. Seems like the overall guidelines of the EF scale have been completely manipulated into what each National Weather Office simply wants. Some are very thorough and efficient with their surveys while some are missing DAT’s and simply don’t have an explanation why such was rated as. I guess an easier way of saying that is they are just simply lazy. Granted that some haven’t seen a true EF5 or F5 to truly get a grasp on how severe the damage needs to look in order to get the rating. But that shouldn’t be an issue when you know what to exactly look for. All of them needed schooling and get qualified in some aspect to do what they do.

Completely agreed. The standard in application with the scale is wildly different between offices. I also agree with your other point the problem has bled into lower ratings as well.

The outstanding case was the Bowling Green Dec 2021 tornado. In no world should this damage have ever received EF2/130



This was a brick, well bolted home that was completely swept, with wind rowing and even some moderate debris granulation to the North. I understand there were failures in construction and possibly a report of a vehicle impact, but at the very minimum this deserves EF3. This particular DoD has a *LB* of 165 and it makes no sense to go 35mph below even that - especially when considering its a poured foundation with sill plates and connections, AND the context.

I think both the Dec 10th 2021 and March 31st 2023 outbreaks, probably the 2 standout outbreaks of the last 10 years in my opinion, featured more violent tornadoes than rated. Dec 2021 you could make an argument for Defiance, MO being an EF4. Construction definitely not the best but the context was marginally supportive, and we've seen plenty of EF4 rated damage similar to the right image in the 2007-2014 era of the EF scale. Especially wit that segment of basement wall being damaged.


The Dresden TN tornado of the same day looked violent on the radar, though I so far haven't seen any photos that scream EF4 intensity though thats not to say it wasn't - the survey was (understandably) quite brief with only a couple structures in town seemingly surveyed.

Lastly I would say Bowling Green probably deserved EF4, partly as seen above, but also that warehouse on the NE town which was rated EF4 for about an hour before it was declared a "mistake". So I reckon Dec 10th probably had 3-4 violent tornadoes in total.

Edit: adding this tweet I have just seen in now

 

[buckeye05]

I do agree that Bowling Green probably deserved EF4, but it was more than a “possible vehicle impact” at that one particular home. An entire storage building and all the heavy equipment inside pretty much slammed into that residence. I normally hate “debris loading” drivel in regards to lowered ratings, but this seems like one of those cases where there’s actually some validity. EF2 is too low though regardless.

Personal rant here, but my big issue with debris loading/collateral damage arguments as justification for low ratings comes into play when there is no traceable object, vehicle, or structure that the surveyors can specify as the source of the collateral damage (Vilonia anyone?), and just say “oh well the tornado just hit a subdivision or downtown area, and it was full of debris, so really hard to prove a violent rating”. I mean yeah? That’s just what happens when violent tornadoes hit structures. By that logic, you can downgrade any violent-rated tornado that directly impacted a sizeable town or city, which is absurd obviously. My reply? Go find me a violent tornado that DOESN’T become filled with debris after striking a populated area. Laughable, and usually an absolute nothing-burger of a talking point when it comes to ratings.

 

[UK_EF4]

March 31st 2023 was again another high-end outbreak which probably had more violent tornadoes than rated. Certainly agree with you that Robinson was at least of EF4 intensity, aerial showed lots of destroyed homes and with quite significant contextual damage. Don't think its extremely underrated though due to the fact most of the homes surveyed don't seem well constructed. I feel like I remember some people saying not all of the damage was surveyed but I can't quite remember if/where this is.

View attachment 34050View attachment 34051
View attachment 34052

I also think that the tornadoes in TN were probably violent. The tornado near Covington was likely EF4 intensity - ripped out a massive electrical transmission tower from the ground. Destroyed some less well constructed homes and had moderate scouring and debarking in some photos. I also don't this is a massive mis-application of the scale. EF3/165 nowadays is probably the most realistic, but again in the early era of the EF scale, and even at a different office, I do reasonably think this would have gotten EF4 context and structural damage considered.
View attachment 34053View attachment 34054

Then the 86 mile Purdy/Bethel Springs TN tornado was very likely violent, even quite violent. Produced some asphalt scouring and destroyed a couple buildings which the NWS surveyed, and I think was not rated too inappropriately given construction concerns.


But the worst damage (in my opinion) wasn't surveyed: Homes destroyed, some apparently well-built, accompanied by debris granulation, wind rowing and some fairly severe tree damage. Overall points towards at least low EF4 intensity, and I don't blame the NWS for not being able to survey all locations given the massive amount of track they had to cover.




Overall, I don't think there were any egregious EF rating cases from this outbreak, but certainly think there were 3-4 violent tornadoes, and likely pre 2014 most of those tornadoes would have been rated as such. This has turned into more of a tornado history post rather than EF debate, so apologies, but I thought it would be interesting to share here regardless.

Edit: it seems none of the photos I copied and pasted in the first half of the post have gone through. I will try and fix this!

 

[UK_EF4]

I do agree that Bowling Green probably deserved EF4, but it was more than a “possible vehicle impact” at that one particular home. An entire storage building and all the heavy equipment inside pretty much slammed into that residence. I normally hate “debris loading” drivel in regards to lowered ratings, but this seems like one of those cases where there’s actually some validity. EF2 is too low though regardless.

Personal rant here, but my big issue with debris loading/collateral damage arguments as justification for low ratings comes into play when there is no traceable object, vehicle, or structure that the surveyors can specify as the source of the collateral damage (Vilonia anyone?), and just say “oh well the tornado just hit a subdivision or downtown area, and it was full of debris, so really hard to prove a violent rating”. I mean yeah? That’s just what happens when violent tornadoes hit structures. By that logic, you can downgrade any violent-rated tornado that directly impacted a sizeable town or city, which is absurd obviously. My reply? Go find me a violent tornado that DOESN’T become filled with debris after striking a populated area. Laughable, and usually an absolute nothing-burger of a talking point when it comes to ratings.

That's fair enough, and a reasonable point. I'd still really like to understand the thought process behind the decision more, from the NWS's point of view.



This is Satellite imagery from 2019, with the imagery right after the tornado on the right. It seems the core (which was quite narrow) of the tornado tracked pretty much just over or a tad north of the home, based on the debris field. The purple circled structure is what I assume to be the machinery shed/storage building. I am very curious about this, no.1 because the shed seems quite small and no. 2 I cant see any easily identifiable massive debris in the remnants of the home. I am *not* saying this impact didn't happen, but there is a part of me thinking that this impact seems pretty similar to normal debris that will hit a home when a tornado strikes it (which leads off into the points you mentioned in the second paragraph- in which I firmly agree). Besides, there is so much talk of the EF scale being a *damage* scale not windspeed, and then in cases like the actual *damage* isn't taken into consideration, and the focus is reasons why the windspeed was lower? It's the tornado doing all the damage anyway - and it takes an intense/violent tornado anyway to turn debris into something which can slab a home in the first place.

 

[AJS]

This is just my personal opinion, feel free to chime in. But I feel like the only appropriate tornado to receive the “dreaded 190 rating” is Washington 2013. Obviously a violent tornado, I don’t remember seeing anything that looked like it was the in realm of EF5 damage unlike some of the other tornadoes before it? Correct me if I’m wrong, obviously Goldsby and Chickasha were two notorious storms that definitely should've gotten an EF5 rating.

I do agree with you about Washington. however, I do think some of the damage caused by that tornado does get overlooked as there was some pretty nasty debarking and granulation of debris in some spots. But I do agree high end EF4 was the right call.

 

[AJS]

I do agree that Bowling Green probably deserved EF4, but it was more than a “possible vehicle impact” at that one particular home. An entire storage building and all the heavy equipment inside pretty much slammed into that residence. I normally hate “debris loading” drivel in regards to lowered ratings, but this seems like one of those cases where there’s actually some validity. EF2 is too low though regardless.

Personal rant here, but my big issue with debris loading/collateral damage arguments as justification for low ratings comes into play when there is no traceable object, vehicle, or structure that the surveyors can specify as the source of the collateral damage (Vilonia anyone?), and just say “oh well the tornado just hit a subdivision or downtown area, and it was full of debris, so really hard to prove a violent rating”. I mean yeah? That’s just what happens when violent tornadoes hit structures. By that logic, you can downgrade any violent-rated tornado that directly impacted a sizeable town or city, which is absurd obviously. My reply? Go find me a violent tornado that DOESN’T become filled with debris after striking a populated area. Laughable, and usually an absolute nothing-burger of a talking point when it comes to ratings.

Been a while since i’ve seen you post here. Welcome back!