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Enhanced Fujita Ratings Debate Thread (1 Viewer)


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335
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Madison, WI
FWIW, 2003 and 2004 each had what I would consider a climatologically normal number of F4 tornadoes, most of them stemming out of the active periods in May of both years.
 

Meteorologist Bobby Best

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Lori, it is generally very difficult to accurately tell the difference between EF4 and EF5 wind speeds. because once winds exceed 170 mph......most structures, and all vehicles, trailers, etc will be destroyed. .
I don't agree with you there, that is if you know what your doing and specifically what to look for!!! As for the topic, I hate the enhanced scale!!!
 
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78
Location
Center Point Alabama
The flaw with the EF scale and the F scales before it, is that it is strictly a damage scale. Wind speed estimates are added on after the scope of the damage has been completely realized. While the scale does have guidelines the interpretation of those guidelines and the application of the ratings is done by humans, and as humans will often do, their will generally be differences of opinion. The line between EF-4 and especially high end EF-4 and EF-5 is far from clear cut it's more like splitting hairs to be honest. I would almost prefer using categories such as weak, strong, and violent. Another potential problem for the EF scale is that with better construction will it eventually become useless anyways?
 

warneagle

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The flaw with the EF scale and the F scales before it, is that it is strictly a damage scale. Wind speed estimates are added on after the scope of the damage has been completely realized. While the scale does have guidelines the interpretation of those guidelines and the application of the ratings is done by humans, and as humans will often do, their will generally be differences of opinion. The line between EF-4 and especially high end EF-4 and EF-5 is far from clear cut it's more like splitting hairs to be honest. I would almost prefer using categories such as weak, strong, and violent. Another potential problem for the EF scale is that with better construction will it eventually become useless anyways?
No, it'll just need to be updated for different construction standards; of course, it's still a question of applying a wind speed to damage to a structure based on those standards, and that's always going to have some flaws since you can't account for unique features of certain buildings, minor topographical features that could have influenced the damage to that structure, etc. That's why contextual damage is so important (even though you don't always get all the same contextual damage even in storms of relatively similar strength).
 

PerryW

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I don't agree with you there, that is if you know what your doing and specifically what to look for!!! As for the topic, I hate the enhanced scale!!!

You don't agree with me? Well Bobby, we'll just have to disagree. I began researching wind speed vs wind damage assessments more than four decades ago; am a student of legendary tornado researcher Dr.Theodore T. Fujita. In September of 1992, I drove down to south Dade county, Florida and surveyed hurricane Andrew's north eyewall as likely possessing sustained winds of at least 155-160 mph, with peak gusts of 190-200 mph. At the time, I was scoffed at by a few meteorologists, including two at NHC, but none are laughing at me since 2002 when NOAA's Hurricane Research Division upgraded Andrew's landfall intensity in south Florida from 145 mph (gusting to 175 mph)......to 165 mph (gusting to 200 mph).
 

Meteorologist Bobby Best

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You don't agree with me? Well Bobby, we'll just have to disagree. I began researching wind speed vs wind damage assessments more than four decades ago; am a student of legendary tornado researcher Dr.Theodore T. Fujita. In September of 1992, I drove down to south Dade county, Florida and surveyed hurricane Andrew's north eyewall as likely possessing sustained winds of at least 155-160 mph, with peak gusts of 190-200 mph. At the time, I was scoffed at by a few meteorologists, including two at NHC, but none are laughing at me since 2002 when NOAA's Hurricane Research Division upgraded Andrew's landfall intensity in south Florida from 145 mph (gusting to 175 mph)......to 165 mph (gusting to 200 mph).
There's nothing at all wrong with disagreeing with others... Very often that can be the spring to studying and re-looking at events and learning from mistakes and learning new things that forward the science, be it meteorology or another, totally different field. It sounds as if you're taking my statement personally though, that was NOT my intention at all! I was just stating my personal opinion. I'm obviously very familiar with Dr Fujita's work. His work forwarded the science as much or more than any other in this field to date.

Without a doubt, Dr Fujita was well ahead of his time.... My point was with the Enhanced Fujita Scale, compared to Dr Fujita's original scale, that actually included an F-6 level and according to a fellow meteorologist that I trust, Dr Fujita personally considered rating an Alabama tornado in the mid to late 1970's as an F-6 (that would, according to Dr Fujita be where the difficulty in determining damage and wind assessment would especially come, between F-5 and F-6).....

I have a personal gripe with the Enhanced scale, for multiple reasons... However, my personal point was, if one knows what they're looking for, the difference between an EF-4 and EF-5 can be determined. Now had the discussion been about the differences between an F-4 and F-5 in Dr Fujita's original scale, I would agree that the differences become harder to determine, but still I would think a student of Dr Fujita's would agree that even then, if one knows what to look for, in a ground survey, it can be accomplished!

I also believe that the Enhanced Fujita Scale is VERY confusing to the general public!!! That is one of many gripes I have with the Enhanced Scale, which is what I was speaking to... Were we to use the Enhanced scale's rating factors, to judge MANY past tornadoes pre-2007, there would be a substantial number of pre-2007 F-4 tornadoes, that would now be rated as EF-5's.....

Let's go a different direction though... Take the April 27, 2011 Tuscaloosa tornado, that hit my market's main population center and the tornado that got so much more publicity, due to two main factors, in my opinion; 1) the fact that it plowed through a downtown metro-population center on nation wide TV and 2) because that's the tornado that the President choose to visit the site of.... I surveyed that storm, in multiple counties that it plowed through, not just Tuscaloosa. I remember so many in and out of the industry, some with FAR more knowledge and experience that I have, that were calling for an EF-5 rating of that storm. Based on the Enhanced scale, I believe that it was rated properly. However, had we still been under the guidelines on the original Fujita scale, in the Tuscaloosa Metro area, that tornado would only have been rated as a F-3!

I said all of that to make this point, someone that knows what they are looking for, can tell the difference between an ENHANCED-F-4 tornado's and an ENHANCED-F-5 tornado's damage rating, if they are doing an on the ground survey of the damage! The step by step process for rating tornadoes, using the Enhanced Fujita Scale, is still available on the Texas Tech University's website at; http://www.depts.ttu.edu/nwi/Pubs/FScale/EFScale.pdf and if one follows that process, I stand by my original opinion, as I stated.....

As for what you brought up concerning Hurricane Andrew.... I don't personally know you and I wasn't personally on the ground in Florida after Andrew. Based on a number of different papers and even a doctoral thesis I've read, over the years, I do agree with the adjustments that NOAA made, years later. What exactly that had to do with, or precisely what specific role you personally played in NOAA's adjustment to Andrew's wind speed, I don't know, again I don't know you personally.... I do believe that everyone that works in the various different areas of meteorology and the geo-science field should be working toward the advancement of the science though, from their perspectives, knowledge, educations, and positions. Me, I'm a simple broadcaster and that is the area I try to keep myself in, however I do play my small part in the field.... If the advancement of the science is truly the intention of someone in the field, then I believe that disagreements and debates, along with the presentation of facts and hardcore science CAN forward our field. However, if we are to do this successfully, I do believe that we must place principals before personalities! As Albert Einstein said; "Try not to become a man of success, but rather try to become a man of value."

Best of luck to you in your future endeavors. Thanks for the work you've done and I hope that you'll continue to do! Many don't realize just how "young", for lack of a better word, our science still is! Oh yes, we have made leaps and bounds, especially in the past 40-45 years, the past 25-30 in particular, but we are still FAR from being an exact science! It is, in my opinion, the work of good and dedicated men, like yourself and especially the generations coming up behind us, that will continue to advance this science. We don't all have to agree, but it does further the science, in my humble opinion, if we are at least open minded, not boisterous, and leave our pride at the door....

Again, best of luck to you and maybe I'll get to know you better in the future and learn from your wisdom and experience, but this is one area, I guess we will have to agree to disagree on...... Have a fantastic day!!!
 

PerryW

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There's nothing at all wrong with disagreeing with others... Very often that can be the spring to studying and re-looking at events and learning from mistakes and learning new things that forward the science, be it meteorology or another, totally different field. It sounds as if you're taking my statement personally though, that was NOT my intention at all! I was just stating my personal opinion. I'm obviously very familiar with Dr Fujita's work. His work forwarded the science as much or more than any other in this field to date.

Without a doubt, Dr Fujita was well ahead of his time.... My point was with the Enhanced Fujita Scale, compared to Dr Fujita's original scale, that actually included an F-6 level and according to a fellow meteorologist that I trust, Dr Fujita personally considered rating an Alabama tornado in the mid to late 1970's as an F-6 (that would, according to Dr Fujita be where the difficulty in determining damage and wind assessment would especially come, between F-5 and F-6).....

I have a personal gripe with the Enhanced scale, for multiple reasons... However, my personal point was, if one knows what they're looking for, the difference between an EF-4 and EF-5 can be determined. Now had the discussion been about the differences between an F-4 and F-5 in Dr Fujita's original scale, I would agree that the differences become harder to determine, but still I would think a student of Dr Fujita's would agree that even then, if one knows what to look for, in a ground survey, it can be accomplished!

I also believe that the Enhanced Fujita Scale is VERY confusing to the general public!!! That is one of many gripes I have with the Enhanced Scale, which is what I was speaking to... Were we to use the Enhanced scale's rating factors, to judge MANY past tornadoes pre-2007, there would be a substantial number of pre-2007 F-4 tornadoes, that would now be rated as EF-5's.....

Let's go a different direction though... Take the April 27, 2011 Tuscaloosa tornado, that hit my market's main population center and the tornado that got so much more publicity, due to two main factors, in my opinion; 1) the fact that it plowed through a downtown metro-population center on nation wide TV and 2) because that's the tornado that the President choose to visit the site of.... I surveyed that storm, in multiple counties that it plowed through, not just Tuscaloosa. I remember so many in and out of the industry, some with FAR more knowledge and experience that I have, that were calling for an EF-5 rating of that storm. Based on the Enhanced scale, I believe that it was rated properly. However, had we still been under the guidelines on the original Fujita scale, in the Tuscaloosa Metro area, that tornado would only have been rated as a F-3!

I said all of that to make this point, someone that knows what they are looking for, can tell the difference between an ENHANCED-F-4 tornado's and an ENHANCED-F-5 tornado's damage rating, if they are doing an on the ground survey of the damage! The step by step process for rating tornadoes, using the Enhanced Fujita Scale, is still available on the Texas Tech University's website at; http://www.depts.ttu.edu/nwi/Pubs/FScale/EFScale.pdf and if one follows that process, I stand by my original opinion, as I stated.....

As for what you brought up concerning Hurricane Andrew.... I don't personally know you and I wasn't personally on the ground in Florida after Andrew. Based on a number of different papers and even a doctoral thesis I've read, over the years, I do agree with the adjustments that NOAA made, years later. What exactly that had to do with, or precisely what specific role you personally played in NOAA's adjustment to Andrew's wind speed, I don't know, again I don't know you personally.... I do believe that everyone that works in the various different areas of meteorology and the geo-science field should be working toward the advancement of the science though, from their perspectives, knowledge, educations, and positions. Me, I'm a simple broadcaster and that is the area I try to keep myself in, however I do play my small part in the field.... If the advancement of the science is truly the intention of someone in the field, then I believe that disagreements and debates, along with the presentation of facts and hardcore science CAN forward our field. However, if we are to do this successfully, I do believe that we must place principals before personalities! As Albert Einstein said; "Try not to become a man of success, but rather try to become a man of value."

Best of luck to you in your future endeavors. Thanks for the work you've done and I hope that you'll continue to do! Many don't realize just how "young", for lack of a better word, our science still is! Oh yes, we have made leaps and bounds, especially in the past 40-45 years, the past 25-30 in particular, but we are still FAR from being an exact science! It is, in my opinion, the work of good and dedicated men, like yourself and especially the generations coming up behind us, that will continue to advance this science. We don't all have to agree, but it does further the science, in my humble opinion, if we are at least open minded, not boisterous, and leave our pride at the door....

Again, best of luck to you and maybe I'll get to know you better in the future and learn from your wisdom and experience, but this is one area, I guess we will have to agree to disagree on...... Have a fantastic day!!!
Bobby, my humble apologies if I came off too strong. I agree with you today and when the Enhanced Fujita scale was implemented in 2007 that it was not going to be accurate in all situations. There were flaws with the original Fujita-Pearson rating scale created in the 1970's, and the EF-scale. The only reason I mentioned hurricane Andrew in 1992 was it was a great success of mine, even though it took more than a decade for wind damage and hurricane researchers with the Hurricane Research Division of NOAA to reevaluate the sustained winds from 145 mph to 165 mph utilizing new technology, including eyewall dropsondes. Unfortunately, my days of researching wind speed vs damage is nearing an end, as I'm battling stage 4 sarcoma, and only have a life expectancy of a few more months per my Oncology team at Emory University Hospital in Atlanta.

I wish you great success and again offer my apologies.

Yours Truly,
Perry
 

Meteorologist Bobby Best

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Bobby, my humble apologies if I came off too strong. I agree with you today and when the Enhanced Fujita scale was implemented in 2007 that it was not going to be accurate in all situations. There were flaws with the original Fujita-Pearson rating scale created in the 1970's, and the EF-scale. The only reason I mentioned hurricane Andrew in 1992 was it was a great success of mine, even though it took more than a decade for wind damage and hurricane researchers with the Hurricane Research Division of NOAA to reevaluate the sustained winds from 145 mph to 165 mph utilizing new technology, including eyewall dropsondes. Unfortunately, my days of researching wind speed vs damage is nearing an end, as I'm battling stage 4 sarcoma, and only have a life expectancy of a few more months per my Oncology team at Emory University Hospital in Atlanta.

I wish you great success and again offer my apologies.

Yours Truly,
Perry

You owe me no apology at all! I love a good debate. Let's just lay this one up to not knowing each other! I was a member of the old group, but more of a lurker, as I will continue to be more with this new 'edition', if you will, of Talk Weather! I am the first to admit, I am FAR from an expert in the science of meteorology. Until the second "Super Tornado Outbreak" that I personally went through, I was nothing but a self educated weather geek and professional commercial broadcaster! lol I'm not much more than that today, but everything I went through, as a commercial broadcaster, amateur radio operator, and storm spotter, when some of the bigger colleges and universities started offering online geo-science and broadcasting degrees and certifications, I took advantage of that!

One day though, I may take the time to stand up on my soapbox and preach a sermon about what I especially believe in and that's more of a commercial broadcast gripe, than a meteorological one! I come from the old days of radio and hate to see what's become of my industry as a whole, but especially what has become of it from a weather standpoint!!! I'll save that post for another day though....

Seriously though Perry, no apology at all is needed! If I came across harsh to you, that was not my intention at all.... Being an old radio man, commercial and amateur, I've been know, on more than a few occasions, to get on a roll and just go! In fact, I stay in hot water on a semi-regular basis with my management in commercial radio for sending emails that are WAY to long and FAR more detailed than they care to read! I forget that not everyone, like those of us that are members of this group, are as interested in, the details of weather as we all are, here on this sight!

It's all good on my end Perry, no worries at all! I do hope we get to know each other better in the future!


Bobby
 
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399
Location
Niagara Falls, Ontario
It's pretty much beating a dead horse at this point, but what is going on with this one?

I can understand an EF3 rating if grass is scoured from one hillside or in a streak a few feet long, but this is ridiculous...Grass scouring has always been one of the best indicators of a violent tornado (more than a slabbed house ever has, to be honest). Now with the current La Plata syndrome I seriously doubt they would have pulled the trigger on an EF4 rating, since that would have made this the first F4/EF4 tornado in Wyoming since 1987, but widespread grass scouring is definitely a strong indicator of a tornado at EF4 strength or higher.

This also makes me seriously doubt that the Plainfield, IL, Chandler, MN, and Philadelphia, MS tornadoes would have been rated F5/EF5 in 2018 since their ratings were based on soil and grass/crop scouring.
 

rolltide_130

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It's pretty much beating a dead horse at this point, but what is going on with this one?

I can understand an EF3 rating if grass is scoured from one hillside or in a streak a few feet long, but this is ridiculous...Grass scouring has always been one of the best indicators of a violent tornado (more than a slabbed house ever has, to be honest). Now with the current La Plata syndrome I seriously doubt they would have pulled the trigger on an EF4 rating, since that would have made this the first F4/EF4 tornado in Wyoming since 1987, but widespread grass scouring is definitely a strong indicator of a tornado at EF4 strength or higher.

This also makes me seriously doubt that the Plainfield, IL, Chandler, MN, and Philadelphia, MS tornadoes would have been rated F5/EF5 in 2018 since their ratings were based on soil and grass/crop scouring.
If we used 2017-2018 standards on 4/27, we may have wound up with 0 EF-5s, and I'm only half joking.
 

Kory

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This is what happens when you use proxies. Not only is there human interpretation, you open the door to a multitude of variables. Just looking at soil properties I can name at least 5 (e.g., mineralogy, antecedent soil moisture, vegetation type, aspect, homogeneity, etc) that could affect scouring. Expand that to many different DIs and good luck trying to get a consensus.
 

Equus

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I think scouring can be best regarded as a contextual helper rather than a DI on its own; even though it's obvious that it takes an extremely intense tornado to cause that sort of wind right near the soil surface I agree that it's the variables in scouring that would make it hard to rate for that purpose. Should be able to rate it EF3 at least for doing it, but I doubt most WFOs would do that with no other damage.

NOW SOAPBOX TIME YAY. Not perhaps relevant to the Wyoming case, but, with a couple of minor exceptions, I am of the opinion that Vilonia served as La Plata part 2; the points brought up after La Plata were very valid and perhaps helped prevent over-rating for several years after, but Vilonia to me was an open invitation to consistently nitpick for every minuscule code issues with every structure hit in a desperate attempt to keep the estimates as lower bound as possible. The EF scale is a minimum-damage scale, yes, but I feel that things have gone way too far recently. Look at the swath of high EF2s that swept away homes in recent years. I do not deny construction quality is poor in destroyed homes. I do not at all deny that weaker tornadoes are very much capable of wiping away poorly built homes. Marshall et al are highly regarded professionals and I highly respect their findings, but, why have a six point rating scale if only the first four (or rarely five) are actually able to be used? I absolutely don't want to see a straight-nailed house simply pushed off its foundation and collapse for an EF5 rating, but as there are several pre-1970 F5s on official record that have yet to be removed for doing similar things (since those were rated by students based on newspaper descriptions instead of surveyors) the consistency of what should be a similar rating throughout the times is appalling.

F5s used to be handed out like candy, probably too much, and now we're seeing papers suggesting that, say, Joplin could be lowered to EF3 because the damage plausibly COULD have been done by an EF3 with an extremely heavy debris load. Not to use Joplin as an example too much but it works here. Once again, yes, it's certainly theoretically possible, but, WHY HAVE AN EF4 AND EF5 IF THEY CAN'T BE USED? Massive swaths of cities are leveled and swept completely away with dozens of deaths and the absolute maximum DI that could possibly be applied to marginally built older homes (with many secondary features suggesting EF5) occurs hundreds of times and there are suggestions to downgrade by two categories literally only because it's theoretically plausible to do so. I am all for accurate engineering surveys, but what was once a simple rating scale is now subject to so much nit-picking and what-ifs that we are losing consistency and the point of rating to begin with. One single farmhouse of marginal to decent construction knocked into a flat pile? "EF4." Dozens of blocks of homes and businesses swept clean and granulated in a mile wide swath with over 150 deaths, manhole covers removed, parking lot barriers yanked up? "Well it theoretically COULD have been EF3." Debris load is a big thing, absolutely, and MOST homes there were poorly built, but secondary factors and death/injury ratio and above ground survival rates should weigh more heavily than they do. I'm shocked Moore got an EF5 rating given recent years' lowballing.

I would like to see the criterion for EF5 not requiring massively overbuilt well above code homes - extremely rare given the average quality in the US - be struck at peak intensity and scoured completely clean with absolutely no chance of secondary impact or some other excuse to not lower it to high EF3. Even marginal homes are very rarely swept away, so EF5 level damage is already rare enough that there is no need to be so extremely strict on it; just go lowest end EF5 or whatever rather than higher-end EF5, instead of downgrading a whole category if a home has a single partly rusted anchor bolt or there was a 5% chance someone's refrigerator bumped into the porch railing before the home came apart. There are usually fewer than one or two tornadoes per year that could even plausibly be rated EF5 most years anyway, so we're not going to be tossing them out like candy again. If we're relying on the standards we've had post 2013, though, we may indeed never see an EF5 again, and even EF4 could become impossible. This year we already saw marginally constructed homes being swept away and a WFO trying to go below even the actual lowest bound DI threshold on the EF scale to rate the destruction an EF2. EF4-5 is certainly inappropriate for that, but the consistency is absolutely awful.

The problem isn't in the surveys themselves, I think - I respect the wind engineers and the WFOs immensely; the problem lies in the extreme scrutiny that goes into making sure the ratings this decade are the absolute lowest bound thing they can possibly give. EF4-5 aren't unattainable magical unicorns, they're just numbers that should be applied when decently built homes are leveled and swept away so that we can file the tornado as a tornado that swept decently built homes away. Sort of irrelevant, but until mobile radars can measure the low level winds in every tornado that fails to strike anything (which will be never) the ratings are going to be totally inconsistent with a tornado's actual intensity based on lack of information anyway, so I think the overemphasis on low-end rating everything isn't helping get us any closer to an accurate database, especially when the wind measurements we do have are currently discarded and not really filed anywhere. Some might feel the opposite, that we need to over-study construction quality for an accurate rating, but I say again, why not just cap the scale at EF4 if EF5 is gonna be unattainable. I can think of plausible reasons to rate almost every F5/EF5 ever rated a 3 or a 4, fairly easily, but it doesn't mean we should just because we can. Absolutely document the engineering on every survey, but try to apply consistency to the final rating product.

/soapbox
 
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I get where you're coming from. I don't think it's quite as bad as you say, yet, as every year from 2014-2017 featured at least two official EF4 tornadoes including that Nebraska day in June 2014 with four consecutive tornadoes in the same family being (rightly) rated EF4. Then after none since Rochelle/Fairdale that April, two tornadoes three days apart were rated EF4 in December, 2015.

2017 wasn't a big year for intense tornado production, and of course we chasers/severe enthusiasts have been ready to stick a fork in this year since the 3rd week of May. I think if the atmosphere did present a true high-end outbreak sequence again (do those exist?) that produced many tornadoes capable of violent damage, you would see most of them rated as such unless they just didn't hit much.

That said, Vilonia 2014 is probably the most egregious example of, as you put it, "desperately" using any excuse plausible to assign the lower bound rating. That tornado did textbook F5 damage to well-built, anchor-bolted houses, therefore it should have been rated EF5.

There was a lot of debate about Tuscaloosa II 2011 (yeah, they got hit by TWO tornadoes that April!) and its "high-end EF4," I think a good case can be made for either rating based on the research I've done. In my non-expert opinion I'd have probably gone EF5 just out of deference to the atmospheric conditions that day, 80-mile path, 64 dead, and THROWN (not just pushed over) railroad cars east of Tuscaloosa (when it had its most impressive radar signature but wasn't hitting much of anything else), but that's why I'm not an expert.

Don't get me started on "Joplin was an EF3" though. A tornado simply does not kill >150 people in this day and age without being exceptionally violent.
 
Last edited:

Equus

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Very true, last year had a lot of potential in the spring but something always threw a wrench in it last minute. And while I can't honestly think of very many tornadoes since Vilonia that seem significantly underrated (there are a handful of high EF2s that could plausibly have been bumped to EF3) I'm just saying that it sets a worrying precedent, as with LZK's very sternly defended reasoning on file, it could easily be referenced in any decision to keep the next obvious EF5 at high EF4.

Which... as you said, we really haven't obviously seen again, yet. Chapman had secondary indicators in railroad and vehicle damage that one could certainly debate warranted EF5 (the railroad damage is unprecedented as far as I know for modern day tornadoes striking CWR on Class One RRs) but it fit decently well with high EF4 since the secondary indicators were difficult to rate for and was rated so, and Rochelle was pegged at 200, the top of EF4, with nothing that really stood out to me to warrant going higher. We really haven't seen another Vilonia, but I feel it's a matter of time. I could go pre-Vilonia and argue about the May 24 2011 EF4s, but there was page upon page of that on the old TW so I won't rehash it. It's a borderline case. Maybe I'm just paranoid, but I guess it'll take another Vilonia-like case to see how they'd handle it. We haven't really seen a clear cut EF5 since Vilonia.

I really think that had the Tuscaloosa EF4 happened during any other outbreak, with no other violent tornadoes to compete with, it would have had a slightly better shot at being upgraded. Seeing what happened at Smithville, Phil Campbell/Hackleburg, and Rainsville, I could see it being considered relatively lesser damage when lined up side by side, but the tossing of loaded railcars and the above ground fatality count among other things would lend good contextual support for a plausible EF5. When the intensity seemed to have peaked east of Tuscaloosa/Holt and the tornado went over miles and miles of unpopulated forestland, I think EF5 damage would have been obvious had there been much to hit there. One of those things we'll never really know.

There is another similar paper that insists the December 2000 Tuscaloosa F4 should be downgraded to F2, and while looking at that tornado's damage I could see how F4 might have been just a bit of a stretch (high F3 would probably have covered it) I find it aggravating that there is this much research put into ways to reduce a simple six-point damage rating purely on technicalities far more complex than the original intent of the scale. The research part, that's fine, I appreciate wind engineering studies tremendously, but the scale is often times being over-complicated in a way that seriously hurts consistency. Looking at graphs, it seems fairly clear that there has been a drop in F2+ tornadoes over the last 30 or 40 years even as F0-F1 reports grow dramatically with better observation. While some of it could be climatological, one would think that all things considered there would be more to hit now as population grows; I personally think that it's because a ton of pre-1990 F2-F3 events (ESPECIALLY the 1950-1970, tornadoes on the official database that were, again, rated by students and not surveyors) were overrated, and now we have a few that seem underrated but very few overrated. As long as the old events are overrated and not changed and today's ratings are held to a super tight scrutiny, there is always going to be a disparity that skews statistics.

I don't see this changing that much, really. In short, regarding Vilonia and potential future events, wind engineering and detailed surveys are fascinating, crucial, and important, but I find it absurd to deny large swaths of completely swept clean homes with a high fatality ratio an EF5 rating for minor contextual discrepancies, unless they are literally unconnected sliders a la La Plata. This was not the case, and I will forever disagree with that rating. But I'm not a meteorologist or a wind engineer, just someone confused as to why the damage levels have changed in the last 20 or so years. They say it's the same but it's changed, far more strictly now. Until some of these discrepancies are hammered out, I can't be convinced that F5=EF5.
 

Equus

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I know it won't be published for a while still but every day I am chomping at the bit waiting to get a copy since I heard it was getting updated. There's a long list of dates post-1995 I am eager to see in the Significant Tornadoes format.
 
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399
Location
Niagara Falls, Ontario
I'm fairly big on using non-structural damage indicators to assess a tornado's strength. It's still a long way from exact but it tends to be a bit more predictable than building damage. Ground and crop scouring, and heavy or sturdy and low-built objects being tossed long distances are some of the best indicators in my humble opinion, even if there are still a number of variables. Let's say a tornado sweeps away a house. There are a lot of reasons why, at least in theory, it could be done by an EF2-EF3 tornado. If that same tornado tosses a freight car a quarter mile, or scours 12 inches of soil...I don't think many people will dispute that it's a violent one. It's the reason why I would personally have upgraded the Vilonia, AR, Chapman, KS, and Washington, OK tornadoes to EF5, but left the Rochelle, IL, Tuscaloosa, AL, and Chickasha, OK tornadoes at high-end EF4.

I also definitely agree that the 1950s to the 1970s were definitely much too liberal in terms of tornado ratings. For instance, the NCDC lists 12 F5 tornadoes in the 1950s, but I've only found evidence of five, maybe six at a stretch, of them causing EF5 damage. 11 F5 tornadoes are listed for the 60s, but again, only about six seem to have caused anything that could be considered EF5 damage. They list a whopping 14 F5 tornadoes in the 1970s, but even then I only see 7, maybe 8 at a fairly big stretch, which caused clear EF5-level damage. By the time of the early 1980s, the standards for F5 ratings seem to have become much more reasonable, although it isn't really until the mid to late 1980s that standards for F4 ratings become more in line with what should be expected by EF scale-standards.

As for the current La Plata syndrome, I feel like it has to be down to NWS surveyors not knowing how to properly apply the scale, since construction quality across most of the country is questionable at best. At the same time, I do feel like it's gone way past reasonable conservatism at this point. I pointed out in another thread that if 4/27 happened in 2018, then I seriously doubt the Chilhowee, Pikeville, Rose Hill, Bridgeport, and maybe even Philadelphia tornadoes would have been rated above EF3, while Rainsville probably would not have been rated above EF4. Going further back, 2/5/08 might have ended up with no violent tornadoes at all, 5/4/07 would probably have had Greensburg as a high EF3 or low EF4 and the other tornadoes as EF2 to low EF3 at best*, and 5/4/03 would probably have only had Franklin, KS rated F4.

*I don't know if I would have rated the Greensburg tornado EF5 myself, but I would have at the very least gone with a high-end EF4 rating, and for what it's worth the tornado almost certainly was at EF5 strength over unpopulated areas.

The velocities of 265 mph from the Greensburg tornado are considerably higher than what would be expected based on damage on the EF scale, but very close to what would be expected on the original Fujita scale. Interestingly enough the RaXPol-recorded winds of 185 mph in the 5/18/13 Rozel, KS tornado showed the opposite: quite a bit lower than what you'd expect on the original Fujita scale, but close to what would be expected on the EF scale. At the same time, the 280 mph winds in the El Reno tornado could be consistent with both - either way, they were above the F5/EF5 threshold, but the damage was some of the most extreme ever recorded which suggests to me that the threshold for F5/EF5 damage might be a bit lower than what the Fujita Scale estimates.

My non-expert take on this is that the threshold of EF4 damage is probably around 180 to 190 mph, and the threshold for EF5 damage is probably around 240 to 250 mph.
 
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Austin Dawg

Member
Messages
98
Location
Austin Texas
Vilonia, Chickasha, and Goldsby will still always be the 3 most obvious EF5s that we're errounously rated EF4. Vilonia irks me the most, especially given how the lead surveyor verbaly communicated his incredibly biased interpretation of the EF scale after the event, which was basically a sugar coated version of "I don't believe in EF5 house damage." Not to mention The historical significance of it being the first clear cut instance of EF5 damage in Arkansas state history, yet it wasn't rated as such. Frustrating.

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

As far as Tuscaloosa, I may be in the minority here, but I feel that high-end EF4 is technically the correct rating. At the end of the day, no well-built and anchor bolted homes were swept away by that tornado, and Chastain Manor was nailed directly into a concrete slab, which is honestly terrible construction for such a large building. Given, the damage to the railroad trestle was extremely impressive. So was the Tuscaloosa tornado an EF5? Almost certainly. Did it produce any legitimate, clear-cut EF5 damage? It did not. Kind of a good example of how the scale is not perfect.
Maybe there are too many levels to consider. Maybe I'm simplifying it but it seems like the differences between a 4 and a 5 from a layman's point of view, they are both very catastrophic.
 

Equus

Member
Messages
1,239
Location
Saragossa, AL
Perhaps appropriate to bump this as tornado season kicks into high gear and ratings are already being debated... also to marvel at how we had zero officially violent tornadoes last year for the first time in modern record keeping in the US. There were surprisingly few candidates, even.

My main eyebrow-raiser right now is the Hamilton, MS EF2, but let's see what other tornadoes pop up in the discussion.
 
Messages
335
Location
Madison, WI
Couple of great posts by Equus and SilentShadow87 that in my opinion sum up the current issues with application of the EF-scale quite well.

This is in jest, but perhaps we need to go back to the "Incredible damage" descriptor from the old Fujita scale. This would encompass things like the destruction of the Cactus-117 oil rig in El Reno '11, the removal of rebar-attached concrete parking stops at Joplin, the damage to the Lingerfelt Road property at Rainsville, and the trench-digging at Philadelphia, MS to name just a few off the top of my head.

"It measures the intensity of a tornado by how much it eats."
"Eats?"
"-Destroys."

Succinct, while Dr. Harding was not quite accurate in that the rating is based not on how much is "eaten" but on to what degree things are eaten compared to the degree to which they resist being eaten.
 

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