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Enhanced Fujita Ratings Debate Thread

Oh so literally ripping the foundation out of the ground in chunks, or uprooting sections of basement wall doesn't matter then?

"the intensity of the tornado has nothing to do with it"

yeah, that's kind of the entire problem, dude.
the whole intensity discussion is a whole other can of worms, im just pointing out UB has to do with construction, not the nature of the damage
 
yeah, for a home to get UB it has to be insanely wellbuilt. i dont know the exact specifications required, but to my knowledge, the only 2 tornados ever considered for a UB rating in the EF scale era was one very wellbuilt mansion in hackleburg, and the home that recieved an F5 rating in Elie (F5 rating, but the EF scale was basically used unofficially)
This home destroyed by the Etna, AR tornado in 2011 was constructed with a steel frame anchored with J-bolts, and got a 166MPH EF4 rating despite there being interior walls left standing. Had the Etna tornado been an EF5, I can imagine this home would have gotten considered for an upper-bound rating. Of course, this brings up that a surveyor expecting that a home has to be as well constructed as the one in Etna to be considered for UB is an extremely unrealistic expectation for multiple reasons.
845405847-1306364835753-1-jpg.5912
 
This is precisely why the EF scale is so counterintuitive though. Why are we applying a windspeed estimate (proportional to the intensity of a tornado) to a scale that is strictly based on engineering? We already have strong evidence that the windspeeds are drastically underestimated when we purely go by the scale’s parameters, yet the current mindset with the scale is to continue to shift the goalpost of EF5 further into impossible territories - despite us having precedent of EF5 level damage not always having to occur with extremely well-built frame homes. (Piedmont, Philadelphia, Joplin)

If the calculation was inaccurate, then by today’s standards, it never would have been used as a DI, and the tornado wouldn’t have had another EF5 DI, so it would have been given an EF4 rating, which is pretty egregious imo. I will take a step back on my previous statement stating that it “clearly took winds well in excess of 210 mph” because that may not be true, I didn’t do any calculation here and I’m not a wind engineer. However, if Cactus is a one-of-a-kind DI with unique geometry and inaccurate wind calcs, then a greater effort needs to be made to incorporate clear EF5 tree damage, an example of complex geometry in something that isn’t one-of-a-kind. More specifically, tornadoes like Matador.
"Why are we applying a windspeed estimate (proportional to the intensity of a tornado) to a scale that is strictly based on engineering" because there isn't enough research into non structural DIs (contextuals n stuff) to accurately put windspeeds on them, structural DIs are the only that can be relatively consistent. you need to recognise that a windspeed assigned to a DI is the absolute minimum that can be 100% confirmed, which is why engineering and construction quality is so important in the scale. they can't just throw out random numbers to DIs that have impressive contextual damage if they don't have any scientific backing. im not disagreeing with the windspeed underestimations, i agree thats something that should be a priority to fix. the calculation wasn't inaccurate, as you said it was very clearly above the threshold of 210mph, its just thats the highest they could confidently go without ranging into the realm of speculation. you can't expect them to spend thousands of hours and spending large amounts of money and manpower on estimating the windspeed for one DI, that will likely never be hit again. even if you used all the computing power available to attempt to calculate the exact windspeeds required for cactus, youd still need to make an insane amount of assumptions and simiplications. it just simply isnt possible, i know plenty of people that have tried. the tornado was very clearly EF5 intensity, even the surveyours themselves have agreed that some of the homes had "undeniable EF5 intensity" damage, so im fairly confident that had Cactus-117 not been hit, they still wouldve found a way to rate the tornado EF5, its just in the real world they didn't as the 1 cactus ef5 di was enough. i honestly dont seen any scenario were piedmont doesnt get EF5. finally, in terms of your point tree damage, they NWS is doing a massive amount of research into tree damage recently, and the revision of the EF scale intends to incorporate 2 new tree DIs to replace the current debarking DI. a single tree DI can get rated up to EF4 180mph, and there will be a multi tree DI that can get rated up to EF5 210mph.
 
This house was specifically built to withstand up to 200 mph winds, while it wasn't swept away it was severely damaged so it stands to reason that wind speeds in excess of 200 hit it so by the EF scale logic this is EF5 damage. Of course, Marshall managed to twist this around to prove whatever point he wanted to prove, I guess.
this home didn't actually experience very high winds, most of the damage was due to debris impacts
 
While I do agree that the home experienced EF5 intensity winds (some experts believe that home is a valid indicator of EF5 intensity, despite it not qualifying on the EF scale’s parameters) I don’t think there’s a reasonable way we can calculate the windspeeds there due to the structure only being severely damaged, and it’s not outlandish that HE EF4 did actually impact this location, at least in my opinion.

However, logic should also be used here. This home was outside the core of the path where the most intense damage was located and still dealt with this, so if you do rate this location 200 mph EF4, isn’t it reasonable to assume that EF5 winds occurred away from the structure, and it’s valid to rate it EF5? I don’t see why that’s such a big deal. Scientists are supposed to be pretty conservative, especially for things such as tornadoes, but here the evidence just feels overwhelming.
the dome house wasn't rated 200mph, and it didnt experience very high winds, most of its damage was due to debris impacts
 
@crosby, For what it's worth, you can combine multiple replies into one post to prevent the thread from becoming cluttered. Welcome to TalkWeather, by the way!
sorry, ill try to do that in future

Of course, this brings up that a surveyor expecting that a home has to be as well constructed as the one in Etna to be considered for UB is an extremely unrealistic expectation for multiple reasons.
Weill it is upper bound for a reason, there is a reason the differentiation between UB and EXP exists
 
the dome house wasn't rated 200mph, and it didnt experience very high winds, most of its damage was due to debris impacts
What was it rated then? Did it receive a rating at all?
"Why are we applying a windspeed estimate (proportional to the intensity of a tornado) to a scale that is strictly based on engineering" because there isn't enough research into non structural DIs (contextuals n stuff) to accurately put windspeeds on them, structural DIs are the only that can be relatively consistent. you need to recognise that a windspeed assigned to a DI is the absolute minimum that can be 100% confirmed, which is why engineering and construction quality is so important in the scale. they can't just throw out random numbers to DIs that have impressive contextual damage if they don't have any scientific backing. im not disagreeing with the windspeed underestimations, i agree thats something that should be a priority to fix. the calculation wasn't inaccurate, as you said it was very clearly above the threshold of 210mph, its just thats the highest they could confidently go without ranging into the realm of speculation. you can't expect them to spend thousands of hours and spending large amounts of money and manpower on estimating the windspeed for one DI, that will likely never be hit again. even if you used all the computing power available to attempt to calculate the exact windspeeds required for cactus, youd still need to make an insane amount of assumptions and simiplications. it just simply isnt possible, i know plenty of people that have tried. the tornado was very clearly EF5 intensity, even the surveyours themselves have agreed that some of the homes had "undeniable EF5 intensity" damage, so im fairly confident that had Cactus-117 not been hit, they still wouldve found a way to rate the tornado EF5, its just in the real world they didn't as the 1 cactus ef5 di was enough. i honestly dont seen any scenario were piedmont doesnt get EF5. finally, in terms of your point tree damage, they NWS is doing a massive amount of research into tree damage recently, and the revision of the EF scale intends to incorporate 2 new tree DIs to replace the current debarking DI. a single tree DI can get rated up to EF4 180mph, and there will be a multi tree DI that can get rated up to EF5 210mph.
These are great points, however it’s unlikely an oil rig is “never going to be hit again” I find that highly unlikely. There are going to be a lot more tornadoes in the future, and a good amount more violent ones. Is it unlikely? Yes, but definitely not impossible. Is this me being a little nit-picky with your points? Also yes, lol. First thing that came to mind though.

And yes, thousands of hours have already been spent creating and maintaining this scale (split between many researchers, surveyors and engineers obviously, but still) and it should continue to be improved. In my eyes, it’s not really a matter of debate whether or not we have seen tornadoes since May 2013 that were as violent as Moore (or almost as violent - Moore 2013 is about as bad as it gets). Why have surveyors thrown out contextuals being used to upgrade tornadoes? Philadelphia is a perfect example of a great usage of it, and so is Joplin, although that one was more to maintain an EF5 rating rather than give it.

The way these damage indicators are being tossed around is already inherently subjective and it’s obvious we can see that when comparing HE EF4 surveys nowadays vs. EF5 surveys from 2007-2013. The very strange use of contextuals that should have been to upgrade tornadoes have been being used to omit them from an EF5 rating; perfect examples of this are Mayfield 2021, Vilonia 2014, and Bassfield 2020 (the latter most of which I’m the iffiest on being EF5, but the other two are pretty bad to me). It’s definitely not as objective as we can be. The idea of the EF scale being as objective as possible is definitely wrong, at least at violent intensities, and from what I can see.

Also, welcome to the forum, I forgot to say that earlier. I really appreciate other viewpoints, I like challenging my own. I’ll digress on what I said about Piedmont.
 
Weill it is upper bound for a reason, there is a reason the differentiation between UB and EXP exists
Well, the way the scale is currently applied, literally the only homes that can get rated UB are steel framed and concrete dome homes. How many of those exist in the US, how many of them exist in areas prone to tornadic activity, what is the chance they'll get hit by an EF5 at its peak intensity, and what is the chance the surveyors won't find any structural flaws or contextual discrepancies to downgrade it? The odds of such a coincidence occurring are extremely small.

When the UB for the scale is based on coincidence, that's not scientific, and certainly does nothing to help discern tornado intensity.
 
"yeah, for a home to get UB it has to be insanely wellbuilt."

1309207411-IMG_5170.JPG
Is Anchor bolts every 18 inches not insanely well built? This home (with an entirely scoured yard and debarked shrub), and 7 other exceptionally built homes were assigned the lower bound wind speed for one tornado.

"because there isn't enough research into non structural DIs (contextuals n stuff) to accurately put windspeeds on them"

That's literally what the surveyors are doing. For every well built home with a clean slab there's a contextual to downgrade it. The NWS loves using contextual indicators to downgrade wind speeds. It's the same story with every-single-violent-tornado of the last 11 years. There are now two conclusive studies from the top authorities in the field (NOAA and the DOW team) telling you tornadoes are being significantly underrated. LISTEN TO THEM.

"which is why engineering and construction quality is so important in the scale"

So let the engineers and construction companies have it. The NWS has a responsibility to warn people 300 MPH winds exist. This is an incredibly dangerous lie and is going to keep getting people killed until it's fixed. Don't wait for an F5 to hit downtown Chicago, St. Louis, or Atlanta to fix it. It has to be fixed now. (Edit: accidentally said Chicago twice)

"and there will be a multi tree DI that can get rated up to EF5 210mph."

This isn't good enough. You're underrating tornadoes by 100 mph on a regular basis. A 210 MPH DI for damage that requires 280 mph+ winds isn't a concession. It's jumping the shark.
 
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100% agreed, that is the worst survey in history imo
How much longer is the NWS going to keep letting the ASCE and Tim Marshall walk all over them? This thread has 43 pages of conclusive, irredeemable evidence he is using his authority to perpetuate lies and deception. I don't know his reasons. Frankly, they don't really matter. If the NWS doesn't act, catastrophe is guaranteed.

Just consider this excerpt from a study published in January 2007.
"Results indicate that a large and intense tornado crossing through residential portions of Chicago, Illinois, could result in tragic consequences with winds in excess of 76 m s-1 (170 MPH) impacting 99 km2, substantially destroying up to 239,000 single-and dual-family housing units, occupied by up to 699,000 people, resulting in 4,500-45,000 deaths, and causing substantial damage to over 400,000 homes occupied by over 1,100,000 people." (Source)

According to the NWS, less than 1% of tornadoes contain winds over 165 MPH. In reality, it's over 20%. Based on everything you've seen, and the evidence presented here. Who are you going to stand behind? The most committed scientists in the field, the DOW team, and NOAA.... Or Tim Marshall.
 
The dome was actually from the Chickasha tornado.
sorry, ur right, i always get it mixed up cus a fair few of the dome photos r mislabeled
Another thing is if EF5 winds are correct then why are we getting tornadoes like the Greenfield, IA tornado that had a DOW windspeed of 308-319 mph?
i dont remember saying EF scale winds are accurate, i 100% agree they are massive underestimates.
Really now?
what?
 
What was it rated then? Did it receive a rating at all?

These are great points, however it’s unlikely an oil rig is “never going to be hit again” I find that highly unlikely. There are going to be a lot more tornadoes in the future, and a good amount more violent ones. Is it unlikely? Yes, but definitely not impossible. Is this me being a little nit-picky with your points? Also yes, lol. First thing that came to mind though.

And yes, thousands of hours have already been spent creating and maintaining this scale (split between many researchers, surveyors and engineers obviously, but still) and it should continue to be improved. In my eyes, it’s not really a matter of debate whether or not we have seen tornadoes since May 2013 that were as violent as Moore (or almost as violent - Moore 2013 is about as bad as it gets). Why have surveyors thrown out contextuals being used to upgrade tornadoes? Philadelphia is a perfect example of a great usage of it, and so is Joplin, although that one was more to maintain an EF5 rating rather than give it.

The way these damage indicators are being tossed around is already inherently subjective and it’s obvious we can see that when comparing HE EF4 surveys nowadays vs. EF5 surveys from 2007-2013. The very strange use of contextuals that should have been to upgrade tornadoes have been being used to omit them from an EF5 rating; perfect examples of this are Mayfield 2021, Vilonia 2014, and Bassfield 2020 (the latter most of which I’m the iffiest on being EF5, but the other two are pretty bad to me). It’s definitely not as objective as we can be. The idea of the EF scale being as objective as possible is definitely wrong, at least at violent intensities, and from what I can see.

Also, welcome to the forum, I forgot to say that earlier. I really appreciate other viewpoints, I like challenging my own. I’ll digress on what I said about Piedmont.
i cant remember what it was rated off the top of my head, but it would be on the DAT

while oil rigs getting hit again is probably pretty likely, the chance of tornados strong enough to cause significant damage to the oil rig itself is unlikely. due to the construction of the rigs, its kinda hard to assign different degrees of damage to it, its either destroyed or not destroyed. also like i said, its just not worth the resources.

i agree with most of ur third paragraph, and i agree contextuals should be used more. it feels like they are only used to prevent higher ratings. that being said, i dont think joplin and rainsville are the best examples of ur point. iirc joplin had 22 EF5 DIs, while i know confidently some of them were underserved ratings, i find it hard to believe there wasnt at least one EF5 DI that would stand up today. also philadelphia was a terrible use of contextuals being used to upgrade tornados imo, trenching is just about the most inconsistent contextual, especially with the circumstances of that day, the tree damage was mostly unimpressive compared to most other violent tornados from that day, and vehicle damage doesnt suggest EF5 intensity. i agree it likely reached EF5 intensity for a brief period as it did some real scouring at points in its path, but there is many many many more tornados from that day that were either stronger or deserved an EF5 rating more.

i think a better example of contextuals being used to upgrade a tornado is rainsville, and i think the logic used in rainsville should be applied to most tornados, although maybe a little stricter. rainsville had some impressive structural damage, impressive enough for a high end ef4 rating, and at certain points, it was contextually EF5. the problem in rainsville is that the areas with the most impressive structural damage didnt exactly have clear EF5 contextuals, and the areas with EF5 contextuals didn't have impressive structural damage. the logic they used, examining damage, especially contextuals, in the context of the tornados entire track, makes a lot more sense to me. if a tornado has high end ef4 damage in places that are clearly not its peak intensity, and has clear EF5 contextuals in other locations, i think that should be enough to verify EF5 intensity
 
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