Enhanced Fujita Ratings Debate Thread

[Aaron Rider]

Shifting gears.


Do you think the Shawnee tornado of 5/19/13 was an EF5? I didn't think so at first, but after seeing Oakhurst classify it as one I started to question myself just a tad. I've also dug up some interesting things on Nitter:

This post, in which Nick K. shares a rumor he heard

The most "immediate" Before in a Before/After pic I've ever seen

The post that started it all

And, of course, Ben Holcomb hilariously busting after correctly identifying the location of the main show the day before, because despite it being off topic I still find it funny

What do you say, folks?

Reading through some of these comments (in your links) makes me want to emphasize something I've said before: a lot of this comes down to, do you believe there's such a thing as a "low-end F5." People in some of those links are directly comparing Shawnee to Moore, as if to say, Shawnee had extremely impressive contextual damage, but not as much as Moore (which, granted, was the next day).

And?

How many past tornadoes had contextual damage as monstrous as Moore? Uh, not that many. Sure, some - and if you go back as far as the Pomeroy's and New Richmond's of the world, and add those in with your Woodward's and your Brandenburg's, and later the Jarrell's and Smithville's, you can probably get to a good 20 or so. But the reality is, even most legitimate F5 or EF5 tornadoes are not going to be as insanely violent as Moore. And I happen to think that there are degrees of strength even amongst EF5 level tornadoes. But this, even though unspoken for the most part, is, at least in my view, one reason why even Vilonia, Matador, or Chapman didn't get the Big Rating.

 

[ColdFront]

@Shakespeare 2016 @ColdFront
KNOCK IT OFF! Go argue in your private messages.

Little late to the game there boss, everyone has moved on.. about a day late and a dollar short

 

[N0mz]

Reading through some of these comments (in your links) makes me want to emphasize something I've said before: a lot of this comes down to, do you believe there's such a thing as a "low-end F5." People in some of those links are directly comparing Shawnee to Moore, as if to say, Shawnee had extremely impressive contextual damage, but not as much as Moore (which, granted, was the next day).

And?

How many past tornadoes had contextual damage as monstrous as Moore? Uh, not that many. Sure, some - and if you go back as far as the Pomeroy's and New Richmond's of the world, and add those in with your Woodward's and your Brandenburg's, and later the Jarrell's and Smithville's, you can probably get to a good 20 or so. But the reality is, even most legitimate F5 or EF5 tornadoes are not going to be as insanely violent as Moore. And I happen to think that there are degrees of strength even amongst EF5 level tornadoes. But this, even though unspoken for the most part, is, at least in my view, one reason why even Vilonia, Matador, or Chapman didn't get the Big Rating.

I think the better solution, although more radical, then grouping together low end ef4s and high end ef4s which honestly should be ef5s, would be to create a ef6 rating. I think the precedent was established in the 20th century that the 5 rating was for tornadoes that come up every year or so. I also agree that there are a very select few tornados, every decade or so, that are absolute monsters, head and shoulders above the rest. The way the NWS treats ef5s could be shifted to how they treat an ef6, reserved for once in a decade combinations of absolute destruction and impact on population centers, ie Moore 2013 or Joplin.

 

[WesL]

Little late to the game there boss, everyone has moved on.. about a day late and a dollar short

Appreciate your financial assessment, 'boss'. But around here, I reckon the house decides when accounts are settled, 'dollar short' or not.

 

[Lake Martin EF4]

12 years, huh?

For the anniversary, every single EF5 candidate that I've seen brought up since that day in 2013. Bolded means I agree with it. AMA.

5/31/13 El Reno, OK
11/17/13 Washington, IL
4/27/14 Vilonia, AR
4/28/14 Louisville, MS
6/16/14 Stanton, NE
6/16/14 Pilger, NE (both)
6/16/14 Wakefield, NE
6/17/14 Coleridge, NE
6/18/14 Alpena, SD
4/9/15 Rochelle, IL
5/9/15 Cisco, TX
12/23/15 Holly Springs, MS
5/25/16 Chapman, KS
6/23/16 Funing, CH
2/28/17 Perryville, MO
4/29/17 Canton, TX (not sure which one, maybe both)
6/28/18 Camp Crook, SD
4/12/20 Hope-Sartinville, MS
4/12/20 Bassfield, MS
7/8/20 Dalton, MN
6/24/21 Hodonin, CZ
12/10/21 Monette, AR
12/10/21 Mayfield, KY
3/24/23 Rolling Fork, MS
6/21/23 Matador, TX
5/21/24 Greenfield, IA
5/22/24 Sterling City, TX
3/14/25 Diaz, AR
5/16/25 Marion, IL
5/18/25 Grinnell, KS

And the map I made (note: doesn't include Wakefield or Hope-Sartinville, pretend they're under the Pilger and Bassfield tracks):

Significant Tornado Events

Today is the 18th anniversary of the 2007 Greensburg EF5, so I figured I’d share a few more of the things I’ve got from that day. Here’s an area that was completely devastated south of US-54, multiple homes were completely leveled or swept cleanly away. Contextual damage was extraordinary...

talkweather.com

 

[N0mz]

12 years, huh?

For the anniversary, every single EF5 candidate that I've seen brought up since that day in 2013. Bolded means I agree with it. AMA.

5/31/13 El Reno, OK
11/17/13 Washington, IL
4/27/14 Vilonia, AR
4/28/14 Louisville, MS
6/16/14 Stanton, NE
6/16/14 Pilger, NE (both)
6/16/14 Wakefield, NE
6/17/14 Coleridge, NE
6/18/14 Alpena, SD
4/9/15 Rochelle, IL
5/9/15 Cisco, TX
12/23/15 Holly Springs, MS
5/25/16 Chapman, KS
6/23/16 Funing, CH
2/28/17 Perryville, MO
4/29/17 Canton, TX (not sure which one, maybe both)
6/28/18 Camp Crook, SD
4/12/20 Hope-Sartinville, MS
4/12/20 Bassfield, MS
7/8/20 Dalton, MN
6/24/21 Hodonin, CZ
12/10/21 Monette, AR
12/10/21 Mayfield, KY
3/24/23 Rolling Fork, MS
6/21/23 Matador, TX
5/21/24 Greenfield, IA
5/22/24 Sterling City, TX
3/14/25 Diaz, AR
5/16/25 Marion, IL
5/18/25 Grinnell, KS

And the map I made (note: doesn't include Wakefield or Hope-Sartinville, pretend they're under the Pilger and Bassfield tracks):

Significant Tornado Events

Today is the 18th anniversary of the 2007 Greensburg EF5, so I figured I’d share a few more of the things I’ve got from that day. Here’s an area that was completely devastated south of US-54, multiple homes were completely leveled or swept cleanly away. Contextual damage was extraordinary...

talkweather.com

I think this just makes my point stronger. There is a clear demarcation between ef4s and the ef5s that have been called "ef4s" for a decade. Like IMO London was a lower end ef4 but Mayfield or Plevna was much clearly a step higher.

BUT there should be another level reserved for the most devastating of all time, the inner circle of tornado history, i.e. Moore or Brandenburg that would end up in the "ef6" category.

 

[mariachi507]

I think this just makes my point stronger. There is a clear demarcation between ef4s and the ef5s that have been called "ef4s" for a decade. Like IMO London was a lower end ef4 but Mayfield or Plevna was much clearly a step higher.

BUT there should be another level reserved for the most devastating of all time, the inner circle of tornado history, i.e. Moore or Brandenburg that would end up in the "ef6" category.

I could potentially roll with that idea. It would at least be a solution. Fujita himself debated the existence of the F6 with...I believe...Xenia, Guin, Birmingham (70s), and Lubbock (I should read more about Brandenburg since that's my home state). Grazulis really hyped up Pampa as a candidate, which I'm not sure I'm on board with. It was a badass drillbit though with possibly F5 potential.

There's a clear definite difference between high end and low end EF4's like you mentioned. Which is basically the crux of the whole problem. It's too big of a difference. Whatever the nomenclature, adding the EF6 or designating an EF4+, I'm hoping we see a real fix. The EF5 drought is standing out to even casuals these days since it's became such a talking point.

 

[Grand Poo Bah]

Tbh of all the di’s from Grinnel aside from scouring I don’t see a single DI that is easy to verify as EF4 and it has to be structural. The farmhome from that farmstead was missed by the core. Meaning it stayed standing.

Bringing this over from the severe weather thread. I couldn't disagree more. The lower bound for DOD 10 "slab swept clean" is 165 mph, the expected wind rating for DOD 9 "all walls collapsed" is 170 mph, and the upper bound for DOD 8 "most wall collapsed" is 178 mph. I see an entire town full of these DODs WITH extreme contextuals. 170 mph EF4 is extremely verifiable, even without including some of the most incredible scouring we've seen in a very long time (why wouldn't it be included?). Hell, if anything, it's the bare MINIMUM acceptable rating for this tornado.

Seriously, whoever said ratings "have to be structural"? It's a made up rule no one ever approved of, but everyone adopted anyways. The entire point of rating tornadoes is to use every resource available to make a best guess at the true wind speed. It's absolutely bananas to continually shrug and say "this is the best we can do" when we were literally doing better than this in the 70s 80s and 90s haha.

Here are your EF4 DIs










Going below the thresholds of the scale to assign a 140 mph EF3 rating is ridiculous. These offices are going rogue and defying an EF scale that is already fundamentally broken in so many ways, and somehow making it worse. I seriously don't get it.

 

[A Guy]

Another EF3 in Morganville, Kentucky uprooted corn crops and scoured the ground at the beginning and end of its path. In the middle it basically completely slabbed two homes. Both were once again classified as "all walls collapsed".

In my opinion the contextual tree damage justifies an upgrade to EF4

There's a possibility the example you provided had some clean up, and in any case it might have been poorly anchored.

But I've noticed some surveys use DoD 10 'all walls collapsed' when there's any debris left on the foundation (often with 165/170 as the windspeed). I suppose technically that's right (not 'swept clean'), but IMO misleading.

Few EF4 rated houses seem to meet the minimum of 'all walls collapsed with the debris piled on the foundation'. This even goes for houses that were noted as 'well constructed' or didn't seem to have glaring flaws. The house DI has nine DoD steps (DoD 5 isn't directly concordant with the others). Even with this higher level of precision than the original F scale descriptions (which went straight from 'levelled' to 'carried some distance from foundations'), there seems to be sufficient room between DoDs 9 and 10 to effectively 'round down' and give a lowball speed by ignoring that most debris were swept away, implying a higher than minimal windspeed. Either that or the standard of construction implied to achieve that minimal presentation at 170 mph is unrealistically high.

I think a minimal EF4 could be represented by the following house from the 2019 Beauregard tornado, which was simply noted as 'J bolts walls collapsed' and 170 mph (although being brick rather than weatherboard it would be less inclined to 'sweep away' anyway, and you could quibble about the small section of remaining wall):



Looking at the original paper EF scale paper, it seems to me that they mustn't have read Fujita's original paper very closely or they listened too much to the 'houses shouldn't be EF5' committee members (who instead should have been thanked for their time and removed from the panel). The categories should've been fitted, as Fujita intended, to houses of a good but not impossibly 'superior' construction, rather than using multiple types of structures. The process was hardly precise anyway, the estimates of the six experts for DoD 10 range from 130 (what were they on?!) to 200 mph - twice the range of a category!

 

[Grand Poo Bah]

There's a possibility the example you provided had some clean up, and in any case the house seems to have been poorly anchored, but on the face it's incorrect. I've noticed some surveys use DoD 10 'all walls collapsed' when there's any debris left on the foundation (often with 165/170 as the windspeed). I suppose technically that's right (not 'swept clean'), but IMO misleading.

Few EF4 rated houses seem to meet the minimum of 'all walls collapsed with the debris piled on the foundation'. This even goes for houses that were noted as 'well constructed' or didn't seem to have glaring flaws. The house DI has nine DoD steps (DoD 5 isn't directly concordant with the others). Even with this higher level of precision than the original F scale descriptions (which went straight from 'levelled' to 'carried some distance from foundations'), there seems to be sufficient room between DoDs 9 and 10 to effectively 'round down' and give a lowball speed by ignoring that most debris were swept away, implying a higher than minimal windspeed. Either that or the standard of construction implied to achieve that minimal presentation at 170 mph is unrealistically high.

I think a minimal EF4 should be represented by the following house from the 2019 Beauregard tornado, which was simply noted as 'J bolts walls collapsed' and 170 mph (although being brick rather than weatherboard it would be less inclined to 'sweep away' anyway, and you could quibble about the small section of remaining wall):

View attachment 42947

Looking at the original paper EF scale paper, it seems to me that they mustn't have read Fujita's original paper very closely or they listened too much to the 'houses shouldn't be EF5' committee members (who instead should have been thanked for their time and removed from the panel). The categories should've been fitted, as Fujita intended, houses of a good but not impossibly 'superior' construction, rather than using multiple types of structures. The process was hardly precise anyway, the estimates of the six experts for DoD 10 range from 130 (what were they on?!) to 200 mph - twice the range of a category!

@UK_EF4 responded to my comment in the 15-16th severe weather thread since I posted it in the wrong place (oops), and my response was pretty similar to yours, at least in terms of the thought process.

Whoops! Didn't realize I posted that in the wrong thread. I noticed it was cleaned up as well, but the description I gave was "it basically completely slabbed two homes". Wiping everything away except one wall is a pretty extreme DOD. There was also another mostly slabbed home in the same area. If you look at the pics you posted you'll notice impressive tree damage in the immediate vicinity of that home as well.

View attachment 42964

Pair that with the impressive scouring at both the beginning and end of this tornado's path, and I think EF4 is the result. The post wasn't necessarily a criticism of the surveyors, but more of my own analysis and conclusion.

View attachment 42965View attachment 42966

Here's where I think the tornado lands based on the EF scales own guidelines and the very supportive contextual evidence. Low end EF4.

View attachment 42968

Basically, using the scale as it was written, I think this area is where the tornado belongs. Low end EF4.

 

[Grand Poo Bah]

There's a possibility the example you provided had some clean up, and in any case the house seems to have been poorly anchored.

But I've noticed some surveys use DoD 10 'all walls collapsed' when there's any debris left on the foundation (often with 165/170 as the windspeed). I suppose technically that's right (not 'swept clean'), but IMO misleading.

Few EF4 rated houses seem to meet the minimum of 'all walls collapsed with the debris piled on the foundation'. This even goes for houses that were noted as 'well constructed' or didn't seem to have glaring flaws. The house DI has nine DoD steps (DoD 5 isn't directly concordant with the others). Even with this higher level of precision than the original F scale descriptions (which went straight from 'levelled' to 'carried some distance from foundations'), there seems to be sufficient room between DoDs 9 and 10 to effectively 'round down' and give a lowball speed by ignoring that most debris were swept away, implying a higher than minimal windspeed. Either that or the standard of construction implied to achieve that minimal presentation at 170 mph is unrealistically high.

I think a minimal EF4 could be represented by the following house from the 2019 Beauregard tornado, which was simply noted as 'J bolts walls collapsed' and 170 mph (although being brick rather than weatherboard it would be less inclined to 'sweep away' anyway, and you could quibble about the small section of remaining wall):

View attachment 42947

Looking at the original paper EF scale paper, it seems to me that they mustn't have read Fujita's original paper very closely or they listened too much to the 'houses shouldn't be EF5' committee members (who instead should have been thanked for their time and removed from the panel). The categories should've been fitted, as Fujita intended, houses of a good but not impossibly 'superior' construction, rather than using multiple types of structures. The process was hardly precise anyway, the estimates of the six experts for DoD 10 range from 130 (what were they on?!) to 200 mph - twice the range of a category!

That pic you posted is such a good analog I thought it was the pre cleanup pic from the Morganville tornado lol. Took me a minute to realize it's not. Great comparison!

 

[AJS]

Bringing this over from the severe weather thread. I couldn't disagree more. The lower bound for DOD 10 "slab swept clean" is 165 mph, the expected wind rating for DOD 9 "all walls collapsed" is 170 mph, and the upper bound for DOD 8 "most wall collapsed" is 178 mph. I see an entire town full of these DODs WITH extreme contextuals. 170 mph EF4 is extremely verifiable, even without including some of the most incredible scouring we've seen in a very long time (why wouldn't it be included?). Hell, if anything, it's the bare MINIMUM acceptable rating for this tornado.

Seriously, whoever said ratings "have to be structural"? It's a made up rule no one ever approved of, but everyone adopted anyways. The entire point of rating tornadoes is to use every resource available to make a best guess at the true wind speed. It's absolutely bananas to continually shrug and say "this is the best we can do" when we were literally doing better than this in the 70s 80s and 90s haha.

Here are your EF4 DIs

View attachment 42948

View attachment 42949View attachment 42950
View attachment 42951View attachment 42952
View attachment 42953View attachment 42954
View attachment 42955

View attachment 42956

Going below the thresholds of the scale to assign a 140 mph EF3 rating is ridiculous. These offices are going rogue and defying an EF scale that is already fundamentally broken in so many ways, and somehow making it worse. I seriously don't get it.

I fail to see how this damage is indicative of anything less than an EF4 contextually wise. You’ve got partially debarked trees, some intense vehicle damage, what looks to be some moderate granulation, and some slight scouring apparent. 100% believe the tornado was at EF4 strength through the town.

 

[OH-IOan]

I fail to see how this damage is indicative of anything less than an EF4 contextually wise. You’ve got partially debarked trees, some intense vehicle damage, what looks to be some moderate granulation, and some slight scouring apparent. 100% believe the tornado was at EF4 strength through the town.

Isn't the rating preliminary, though? It isn't like they can't go back and change it pending further information.

 

[AJS]

Isn't the rating preliminary, though? It isn't like they can't go back and change it pending further information.

Yeah, it is preliminary but I really hope they don’t lowball the rating. Because it’s clear to me that the tornado has clear EF4 strength contextually.

 

[OH-IOan]

Yeah, it is preliminary but I really hope they don’t lowball the rating. Because it’s clear to me that the tornado has clear EF4 strength contextually.

100%, I'd even go as far as to say it may have been of high-end EF4 intensity prior to impacting Grinnell. Something really has to be done about the scale soon, we've seen so many incredibly lowballed ratings this year (Bakersfield, Lake City, Selmer, Grinnell, Plevna likely won't be rated as violent).

 

[buckeye05]

Even if the constitution quality in town was poor, Grinnell just has way, way too many violent contextual indicators for low-end EF3 to be appropriate.

I’ve seen:
-major ground scouring
-significant debris granulation
-violent vehicle damage
-severe stubbing and debarking of trees

That in my opinion should be enough for an upgrade, or at least a higher wind speed estimate, but I’m not holding my breath.

 

[OH-IOan]

Even if the constitution quality in town was poor, Grinnell just has way, way too many violent contextual indicators for low-end EF3 to be appropriate.

I’ve seen:
-major ground scouring
-significant debris granulation
-violent vehicle damage
-severe stubbing and debarking of trees

That in my opinion should be enough for an upgrade, or at least a higher wind speed estimate, but I’m not holding my breath.

Do you think they'll actually upgrade Grinnell? I personally doubt it.

 

[AJS]

I honestly am doubting an upgrade. But there’s absolutely no excuse for an EF3 rating. Low end at that.

 

[TheSuckZone]

I honestly am doubting an upgrade. But there’s absolutely no excuse for an EF3 rating. Low end at that.

I don't think they have released anything official but was told 140 mph EF3 damage was found.

 

[OH-IOan]

I don't think they have released anything official but was told 140 mph EF3 damage was found.

The path is on DAT, with 140 mph as peak winds. No comment on whether an upgrade is possible, but they are actively extending and refining the path.