Significant Tornado Events

[Shakespeare 2016]

paper states EF scale is ok for EF0-EF2 but then evreything after is under rated. as for the F scale they state its more acurate however the F0 tend to sligthly be over rated , despite this F0-F3 are in the ok zone while F4-F5 are not.

here is the wind speed vs damage but the damage is using the old F scale.
View attachment 25380
so yes F scale is apparently more acurate to the real tornado winds then the EF scale (well execpt for weak F0)

Another thing is how high can tornadic windspeeds in the most exceptionally tornadoes such as Jarrell, Smithville, Philadelphia, and El Reno 2011. I tend to believe it could be as high as 330+ mph.

 

[joshoctober16]

Another thing is how high can tornadic windspeeds in the most exceptionally tornadoes such as Jarrell, Smithville, Philadelphia, and El Reno 2011. I tend to believe it could be as high as 330+ mph.

well you can finally find out with that graph just plot a official damage point to the graph above (put it in the black line) and find out, ima try to do a chart of what they would be in a bit, but trust me on this that the wind speeds are much higher then anyone would think

 

[joshoctober16]

while i dont have much time at this moment , but here's a general sense.
its interesting to note despite how it seems the winds seem to be too high it is infact possibly more accurate then you think, the andover 2022 tornado was rated 150 mph but had a wind speed measurement of 264 mph, it seems to fit well in that. the wedge that reed intercepted had a high end EF1 rating right beside him but the winds were around 140-160 mph.

 

[Shakespeare 2016]

View attachment 25381
while i dont have much time at this moment , but here's a general sense.
its interesting to note despite how it seems the winds seem to be too high it is infact possibly more accurate then you think, the andover 2022 tornado was rated 150 mph but had a wind speed measurement of 264 mph, it seems to fit well in that. the wedge that reed intercepted had a high end EF1 rating right beside him but the winds were around 140-160 mph.

I doubt tornadic windspeeds can reach close to the speed of sound. I typically thought around 380 mph in the most extreme cases.

 

[joshoctober16]

I doubt tornadic windspeeds can reach close to the speed of sound. I typically thought around 380 mph in the most extreme cases.

we have no windspeed + damage EF5 events as of yet , it would be very weird that EF0-EF3 would be like this but then suddenly the EF4-EF5 stop majorly going up for there wind. speed

 

[A Guy]

True, but the situation with the scale is out of control now.

Somebody PLEASE Fix it!!!! The EF-scale is extremely corrupted.

I think mentality's contributing. IMO Fujita's intent was to discern tornado intensity (hence his use of non-standard indicators), and create damage categories based on a common, relatable structure - the family home. The EF scale comes from a theoretical engineering mentality. Damage is examined and a windspeed is assigned based on the theoretical minimum to cause it. The fullest manifestation of this mindset seems to postdate the EF scale's implementation, as we see greater instance of minimums being used over expecteds, and some surveyors even finding justification to break the bounds of the scale to assign lower windspeeds more recently, and a complete rejection of radar data that didn't apply to Rozel KS but did to everything subsequent.

Two problems arise. Firstly, we can't field test the speeds. While they are based at least partially on empirical data (e.g. wind tunnel tests), tornado wind dynamics are complex and we can't summon up a tornado of fixed intensity to see what actually happens. Secondly, failure would be a probability (don't know what ones they used). That doesn't mean the windspeed wasn't higher when the structure actually failed. If windspeeds are higher then this could make the ASCE hot under the collar as it could imply their standards are suboptimal. The current mentality is based on what windspeeds could be given a set of engineering considerations. If we actually want to understand tornadoes better, I think need to move to a mentality of discerning what the windspeeds actually are.

That said, any EF scale fix must start with the expected value of frame houses being made EF5 again. The original EF scale proposal gave the equivalent value to F5 as being 200 MPH. As mentioned by John Robinson, it was a personal, political decision of one of those involved in the EF scale to change the threshold, and as said by several posters here there's sound reasons to think Robinson was the one responsible. Aligning the categories with Fujita's original intent - a six step scale based on a common structure - would show an important change in mentality.

Adding to that, that's why I think 'contextual damage' can be a red herring. Firstly, in practice we see it used to downrate but never uprate. Secondly, if the category thresholds are repaired to reflect the original intent of the scale, then an EF5 rating should be able to be assigned to a well constructed house without the context needing initial consideration. This isn't to say it shouldn't be considered, but its currently being crucial to achieving EF5 is partly because the thresholds were deliberately misaligned.

Eventually I think the tornado rating mentality needs to change to:
1: We want to discern a tornado's windspeed - what tools do we have and how do we apply them? This means ditching the 'damage only' mentality and working out how radar speeds relate to near-ground, and accepting things like the rare direct measurement (is there any reason the 175 mph measurement from the TIV2 on 27/5/13 shouldn't be accepted?). I'm still a big fan of photogrammetry as a possible solution to some questions.
2: how do we align windspeeds to Fujita's original six-step damage categorisation for frame homes of 'good' construction (but not some 'superior' construction never observed in real life) to make a functional scale? Not 'homes shouldn't be EF5 because that's like my opinion man', which is literally the situation we currently have.

OTOH looking at the IF scale in Europe, they seem to have a sounder and less personally driven basis for their decisions. But I don't like the 'IF2.5' and '3.5' steps. They smack of the false precision of the TORRO scale and are just plain ugly.

 

[SpotlightForRareTornadoes]

I think mentality's contributing. IMO Fujita's intent was to discern tornado intensity (hence his use of non-standard indicators), and create damage categories based on a common, relatable structure - the family home. The EF scale comes from a theoretical engineering mentality. Damage is examined and a windspeed is assigned based on the theoretical minimum to cause it. The fullest manifestation of this mindset seems to postdate the EF scale's implementation, as we see greater instance of minimums being used over expecteds, and some surveyors even finding justification to break the bounds of the scale to assign lower windspeeds more recently, and a complete rejection of radar data that didn't apply to Rozel KS but did to everything subsequent.

Two problems arise. Firstly, we can't field test the speeds. While they are based at least partially on empirical data (e.g. wind tunnel tests), tornado wind dynamics are complex and we can't summon up a tornado of fixed intensity to see what actually happens. Secondly, failure would be a probability (don't know what ones they used). That doesn't mean the windspeed wasn't higher when the structure actually failed. If windspeeds are higher then this could make the ASCE hot under the collar as it could imply their standards are suboptimal. The current mentality is based on what windspeeds could be given a set of engineering considerations. If we actually want to understand tornadoes better, I think need to move to a mentality of discerning what the windspeeds actually are.

That said, any EF scale fix must start with the expected value of frame houses being made EF5 again. The original EF scale proposal gave the equivalent value to F5 as being 200 MPH. As mentioned by Dan Robinson, it was a personal, political decision of one of those involved in the EF scale to change the threshold, and as said by several posters here there's sound reasons to think Robinson was the one responsible. Aligning the categories with Fujita's original intent - a six step scale based on a common structure - would show an important change in mentality.

Adding to that, that's why I think 'contextual damage' can be a red herring. Firstly, in practice we see it used to downrate but never uprate. Secondly, if the category thresholds are repaired to reflect the original intent of the scale, then an EF5 rating should be able to be assigned to a well constructed house without the context needing initial consideration. This isn't to say it shouldn't be considered, but its currently being crucial to achieving EF5 is partly because the thresholds were deliberately misaligned.

Eventually I think the tornado rating mentality needs to change to:
1: We want to discern a tornadoes windspeed - what tools do we have and how do we apply them? This means ditching the 'damage only' mentality and working out how radar speeds relate to near-ground, and accepting things like the rare direct measurement (is there any reason the 175 mph measurement from the TIV2 on 27/5/13 shouldn't be accepted?). I'm still a big fan of photogrammetry as a possible solution to some questions.
2: how do we align windspeeds to Fujita's original six-step damage categorisation for frame homes of 'good' construction (but not some 'superior' construction never observed in real life) to make a functional scale? Not 'homes shouldn't be EF5 because that's like my opinion man', which is literally the situation we currently have.

OTOH looking at the IF scale in Europe, they seem to have a sounder and less personally driven basis for their decisions. But I don't like the 'IF2.5' and '3.5' steps. They smack of the false precision of the TORRO scale and are just plain ugly.

Me too.
I really like the Torro scale. It is better here on the west coast and around the world.

 

[Juliett Bravo Kilo]

Last Wednesday was the 95th anniversary of this event & somehow I forgot about it. Anyways, damage photographs from the Sneed, AR F5 (Arkansas's only official F5, at least according to Grazulis) and other tornadoes from this highly overlooked outbreak:

1 What's left of a home from Sneed on top, Possum Trot on bottom.


2 A farmhouse destroyed near Swifton


3 A school and church near Bono.


4 A car thrown more than 300 yards near Swifton


5 The site of the Pleasant Valley schoolhouse, with debarked denuded trees all around


6 A view of Guion taken several days afterward once Red Cross tents and such had been set up.



7 The Pleasant Valley schoolhouse, with children searching for their books and belongings



8 The Riley home in Sneed:


9 What little was left of a homestead just outside of Sneed:




10 Not sure of the location here:





More info:

 

[joshoctober16]

I think mentality's contributing. IMO Fujita's intent was to discern tornado intensity (hence his use of non-standard indicators), and create damage categories based on a common, relatable structure - the family home. The EF scale comes from a theoretical engineering mentality. Damage is examined and a windspeed is assigned based on the theoretical minimum to cause it. The fullest manifestation of this mindset seems to postdate the EF scale's implementation, as we see greater instance of minimums being used over expecteds, and some surveyors even finding justification to break the bounds of the scale to assign lower windspeeds more recently, and a complete rejection of radar data that didn't apply to Rozel KS but did to everything subsequent.

Two problems arise. Firstly, we can't field test the speeds. While they are based at least partially on empirical data (e.g. wind tunnel tests), tornado wind dynamics are complex and we can't summon up a tornado of fixed intensity to see what actually happens. Secondly, failure would be a probability (don't know what ones they used). That doesn't mean the windspeed wasn't higher when the structure actually failed. If windspeeds are higher then this could make the ASCE hot under the collar as it could imply their standards are suboptimal. The current mentality is based on what windspeeds could be given a set of engineering considerations. If we actually want to understand tornadoes better, I think need to move to a mentality of discerning what the windspeeds actually are.

That said, any EF scale fix must start with the expected value of frame houses being made EF5 again. The original EF scale proposal gave the equivalent value to F5 as being 200 MPH. As mentioned by Dan Robinson, it was a personal, political decision of one of those involved in the EF scale to change the threshold, and as said by several posters here there's sound reasons to think Robinson was the one responsible. Aligning the categories with Fujita's original intent - a six step scale based on a common structure - would show an important change in mentality.

Adding to that, that's why I think 'contextual damage' can be a red herring. Firstly, in practice we see it used to downrate but never uprate. Secondly, if the category thresholds are repaired to reflect the original intent of the scale, then an EF5 rating should be able to be assigned to a well constructed house without the context needing initial consideration. This isn't to say it shouldn't be considered, but its currently being crucial to achieving EF5 is partly because the thresholds were deliberately misaligned.

Eventually I think the tornado rating mentality needs to change to:
1: We want to discern a tornadoes windspeed - what tools do we have and how do we apply them? This means ditching the 'damage only' mentality and working out how radar speeds relate to near-ground, and accepting things like the rare direct measurement (is there any reason the 175 mph measurement from the TIV2 on 27/5/13 shouldn't be accepted?). I'm still a big fan of photogrammetry as a possible solution to some questions.
2: how do we align windspeeds to Fujita's original six-step damage categorisation for frame homes of 'good' construction (but not some 'superior' construction never observed in real life) to make a functional scale? Not 'homes shouldn't be EF5 because that's like my opinion man', which is literally the situation we currently have.

OTOH looking at the IF scale in Europe, they seem to have a sounder and less personally driven basis for their decisions. But I don't like the 'IF2.5' and '3.5' steps. They smack of the false precision of the TORRO scale and are just plain ugly.

i pretty much agree with you in every way, its also annoying they use contextual to downgrade but never to upgrade in todays times.

 

[buckeye05]

i pretty much agree with you in every way, its also annoying they use contextual to downgrade but never to upgrade in todays times.

This. I’ve said it so many times. If you only use it to downgrade, it doesn’t take a statistics expert to know how the will skew all survey results in a certain direction. This discrepancy has never been addressed by a professional or even mentioned by anyone in the field, but it most certainly is a real thing.

Context is a great indicator when it comes to evaluating tornado intensity, and it can either be used or abused. I just wish we saw more of the former than the latter.

 

[UK_EF4]

I think mentality's contributing. IMO Fujita's intent was to discern tornado intensity (hence his use of non-standard indicators), and create damage categories based on a common, relatable structure - the family home. The EF scale comes from a theoretical engineering mentality. Damage is examined and a windspeed is assigned based on the theoretical minimum to cause it. The fullest manifestation of this mindset seems to postdate the EF scale's implementation, as we see greater instance of minimums being used over expecteds, and some surveyors even finding justification to break the bounds of the scale to assign lower windspeeds more recently, and a complete rejection of radar data that didn't apply to Rozel KS but did to everything subsequent.

Two problems arise. Firstly, we can't field test the speeds. While they are based at least partially on empirical data (e.g. wind tunnel tests), tornado wind dynamics are complex and we can't summon up a tornado of fixed intensity to see what actually happens. Secondly, failure would be a probability (don't know what ones they used). That doesn't mean the windspeed wasn't higher when the structure actually failed. If windspeeds are higher then this could make the ASCE hot under the collar as it could imply their standards are suboptimal. The current mentality is based on what windspeeds could be given a set of engineering considerations. If we actually want to understand tornadoes better, I think need to move to a mentality of discerning what the windspeeds actually are.

That said, any EF scale fix must start with the expected value of frame houses being made EF5 again. The original EF scale proposal gave the equivalent value to F5 as being 200 MPH. As mentioned by Dan Robinson, it was a personal, political decision of one of those involved in the EF scale to change the threshold, and as said by several posters here there's sound reasons to think Robinson was the one responsible. Aligning the categories with Fujita's original intent - a six step scale based on a common structure - would show an important change in mentality.

Adding to that, that's why I think 'contextual damage' can be a red herring. Firstly, in practice we see it used to downrate but never uprate. Secondly, if the category thresholds are repaired to reflect the original intent of the scale, then an EF5 rating should be able to be assigned to a well constructed house without the context needing initial consideration. This isn't to say it shouldn't be considered, but its currently being crucial to achieving EF5 is partly because the thresholds were deliberately misaligned.

Eventually I think the tornado rating mentality needs to change to:
1: We want to discern a tornadoes windspeed - what tools do we have and how do we apply them? This means ditching the 'damage only' mentality and working out how radar speeds relate to near-ground, and accepting things like the rare direct measurement (is there any reason the 175 mph measurement from the TIV2 on 27/5/13 shouldn't be accepted?). I'm still a big fan of photogrammetry as a possible solution to some questions.
2: how do we align windspeeds to Fujita's original six-step damage categorisation for frame homes of 'good' construction (but not some 'superior' construction never observed in real life) to make a functional scale? Not 'homes shouldn't be EF5 because that's like my opinion man', which is literally the situation we currently have.

OTOH looking at the IF scale in Europe, they seem to have a sounder and less personally driven basis for their decisions. But I don't like the 'IF2.5' and '3.5' steps. They smack of the false precision of the TORRO scale and are just plain ugly.

Very well said.

 

[Juliett Bravo Kilo]

What did he have to say about the Camp Crook, SD/Capitol, MT 2018 tornado? It was certainly much higher than the low-end EF3 rating it got.

This quote

"Peak winds were estimated at 136 mph. This estimate may have been 60 mph less than its maximum wind speed".

Another crazy thing about this tornado is that the 5-ton tractor it destroyed had its remains spread over a three-mile area.

 

[Shakespeare 2016]

This quote

"Peak winds were estimated at 136 mph. This estimate may have been 60 mph less than its maximum wind speed".

Another crazy thing about this tornado is that the 5-ton tractor it destroyed had its remains spread over a three-mile area.

So using the EF-SCALE that would take it close to the upper limit of an EF4 tornado. Seems reasonable given the things that tornado did.

 

[Shakespeare 2016]

This quote

"Peak winds were estimated at 136 mph. This estimate may have been 60 mph less than its maximum wind speed".

Another crazy thing about this tornado is that the 5-ton tractor it destroyed had its remains spread over a three-mile area.

Yeah, I thought they found some remains of the tractor over 3 miles away.

 

[Shakespeare 2016]

I think mentality's contributing. IMO Fujita's intent was to discern tornado intensity (hence his use of non-standard indicators), and create damage categories based on a common, relatable structure - the family home. The EF scale comes from a theoretical engineering mentality. Damage is examined and a windspeed is assigned based on the theoretical minimum to cause it. The fullest manifestation of this mindset seems to postdate the EF scale's implementation, as we see greater instance of minimums being used over expecteds, and some surveyors even finding justification to break the bounds of the scale to assign lower windspeeds more recently, and a complete rejection of radar data that didn't apply to Rozel KS but did to everything subsequent.

Two problems arise. Firstly, we can't field test the speeds. While they are based at least partially on empirical data (e.g. wind tunnel tests), tornado wind dynamics are complex and we can't summon up a tornado of fixed intensity to see what actually happens. Secondly, failure would be a probability (don't know what ones they used). That doesn't mean the windspeed wasn't higher when the structure actually failed. If windspeeds are higher then this could make the ASCE hot under the collar as it could imply their standards are suboptimal. The current mentality is based on what windspeeds could be given a set of engineering considerations. If we actually want to understand tornadoes better, I think need to move to a mentality of discerning what the windspeeds actually are.

That said, any EF scale fix must start with the expected value of frame houses being made EF5 again. The original EF scale proposal gave the equivalent value to F5 as being 200 MPH. As mentioned by Dan Robinson, it was a personal, political decision of one of those involved in the EF scale to change the threshold, and as said by several posters here there's sound reasons to think Robinson was the one responsible. Aligning the categories with Fujita's original intent - a six step scale based on a common structure - would show an important change in mentality.

Adding to that, that's why I think 'contextual damage' can be a red herring. Firstly, in practice we see it used to downrate but never uprate. Secondly, if the category thresholds are repaired to reflect the original intent of the scale, then an EF5 rating should be able to be assigned to a well constructed house without the context needing initial consideration. This isn't to say it shouldn't be considered, but its currently being crucial to achieving EF5 is partly because the thresholds were deliberately misaligned.

Eventually I think the tornado rating mentality needs to change to:
1: We want to discern a tornado's windspeed - what tools do we have and how do we apply them? This means ditching the 'damage only' mentality and working out how radar speeds relate to near-ground, and accepting things like the rare direct measurement (is there any reason the 175 mph measurement from the TIV2 on 27/5/13 shouldn't be accepted?). I'm still a big fan of photogrammetry as a possible solution to some questions.
2: how do we align windspeeds to Fujita's original six-step damage categorisation for frame homes of 'good' construction (but not some 'superior' construction never observed in real life) to make a functional scale? Not 'homes shouldn't be EF5 because that's like my opinion man', which is literally the situation we currently have.

OTOH looking at the IF scale in Europe, they seem to have a sounder and less personally driven basis for their decisions. But I don't like the 'IF2.5' and '3.5' steps. They smack of the false precision of the TORRO scale and are just plain ugly.

I feel as though especially on the lower bounds of the DOD 10 are done deliberately to make an excuse to underrate tornadoes.

LB...165 mph(EF3)
EXP...200 mph(EF4)
UB...220 mph(EF5)

Why couldn't they be set like this if the idea is to get the highest EF rating possible from a tornado?

LB...166 mph(EF4)
UB...201 mph(EF5)
EXP...221 mph(EF5)

The 165 mph EF3 has been especially abused time and time again by NWS offices. Literally 1 mph away from the next category for both a 165 mph EF3 or a 200 mph(EF4).

 

[Juliett Bravo Kilo]

So using the EF-SCALE that would take it close to the upper limit of an EF4 tornado. Seems reasonable given the things that tornado did.

He does seem to give some tornadoes his own rating, what he said for this one makes sense. And yet, nothing for Vilonia.

 

[HAwkmoon]

View attachment 25381
while i dont have much time at this moment , but here's a general sense.
its interesting to note despite how it seems the winds seem to be too high it is infact possibly more accurate then you think, the andover 2022 tornado was rated 150 mph but had a wind speed measurement of 264 mph, it seems to fit well in that. the wedge that reed intercepted had a high end EF1 rating right beside him but the winds were around 140-160 mph.

It is not possible to have 700 mph tornadoes. Andover is not a good example. I am sorry but saying that EF-2 damage can occur with winds of 201 mph is just untrue.

 

[joshoctober16]

It is not possible to have 700 mph tornadoes. Andover is not a good example.

i never said anything about 700 mph? i was just saying that the study shows that 150 mph damage tends to be apparently made by 261 mph winds, this fits well with andover 2022.

 

[Shakespeare 2016]

He does seem to give some tornadoes his own rating, what he said for this one makes sense. And yet, nothing for Vilonia.

I tend to wonder if he is in cahoots with some of these NWS offices. I just can’t see how the Vilonia 2014 tornado can be anything but EF5.

 

[Juliett Bravo Kilo]

I tend to wonder if he is in cahoots with some of these NWS offices. I just can’t see how the Vilonia 2014 tornado can be anything but EF5.

I'm normally not one for conspiracy theories but with Vilonia I have to wonder. Or maybe John Robinson, the former director of the NWS who retired in 2014 encouraged him to not change or dispute the rating.