Enhanced Fujita Ratings Debate Thread

[ColdFront]

This is an honest question from me: Why in the world is a tree standing within 100 yards(if not less) of violent damage justification to lower the rating of the violent damage? When it's been scientifically proven that subvortices contribute HEAVILY to localized areas of EF5 damage. It just has always felt very excusatory to me; if not semi-unscientific. Tornadic internal winds vary wildly and chaotically; only true slow moving "Grinders" tend to wipe out EVERYTHING in their windfield, or exceedingly rare tornadoes such as Bridgecreek 1999. I really cannot get why this is, but ive heard that Mayfield 2021 was heavily scrutinized for this, plus Goldsby 2011 had a fence cited for rating a home EF4 when it very well could've been EF5.
I get it, EF5 damage is supposed to be incredible, it is supposed to be exceedingly rare; but this does not justify these almost unscientific and random bits of scrutiny. I really would like some sort of explanation from someone who knows more than I. Like even confirmed EF5 tornadoes left trees intact in spots of extreme damages. I just am curious

Then you get the ASCE NIST saying slow movers only exacerbate damage and it’s why Jarrell’s damage was so bad and only contained F3 winds.

You could ask 1000 surveyors and you’d probably get 1000 different opinions. There’s just so much subjectivity involved. I’ve stated it before, but I just don’t even care about ratings anymore. Until we get better technology or methods in the future, the EF scale will continue to be flawed and never accurately measure every tornados intensity. Revision attempts be damned.

 

[Shakespeare 2016]

Then you get the ASCE saying slow movers only exacerbate damage and it’s why Jarrell’s damage was so bad and only contained F3 winds.

You could ask 1000 surveyors and you’d probably get 1000 different opinions. There’s just so much subjectivity involved. I’ve stated it before, but I just don’t even care about ratings anymore. Until we get better technology or methods in the future, the EF scale will continue to be flawed, revision attempts be damned.

That was actually NIST but maybe ASCE was involved as well. ASCE said Joplin was a low-end EF4 based on the most intense damage and we know that is BS.

 

[ColdFront]

That was actually NIST but maybe ASCE was involved as well. ASCE said Joplin was a low-end EF4 based on the most intense damage and we know that is a BS.

Ah, I stand corrected. Thanks for letting me know that. ASCE was indeed the Joplin study authors and NIST for Jarrell.

 

[Shakespeare 2016]

lets not forget the whole , debris hitting the building reasoning that is commonly used starting in 2014 , and the whole tree standing within 100 yards.

smithville and hackleburg were 2 of the EF5 from that outbreak that threw large debris on to other stuff.

Smithville also had a very narrow but long live Violent damage path, however for some odd reason most office sees narrow violent damage as.... not real violent damage for some reason.

however ignoring them 2 main issues smithville has every reason to be EF5.

but yeah.... hackleburgs survey is a mess...
View attachment 39576
(image overlay on the official survey map on google earth)

I went on the DAT and some of the brick houses that were flattened and rated EF5. It was a large pile of rubble setting on the foundation. I would think that would be more in line with a 185 mph EF4 but maybe I am being a little too conservative.

 

[Aaron Rider]

Also, off topic a bit but related to disputed intensities, the list that Rochelle comment was in response to contained some interesting picks:


Never seen Grand Rapids as a Palm Sunday F5 candidate before. That brings us up to 13 from that event. Is there more?
1. Tipton, IA (maybe)
2. Crystal Lake, IL
3. Grand Rapids, MI (maybe)
4. La Paz, IN (maybe)
5. Goshen, IN (maybe)
6. Rainbow Lake, IN
7. Coldwater Lake, MI
8. Sunnyside, IN
9. Kokomo-Greentown, IN
10. Lebanon-Sheridan, IN
11. Toledo, OH
12. Rockaway, OH (maybe)
13. Pittsfield-Strongsville, OH

Also, question for all of you: if you were to reanalyze Palm Sunday 1965, what major (and preferably certain, no "might be" or "would be") rating changes would you make?

What a great post.

I always get confused with two of the names. I assume you're referring to the Midway tornado when you write "Goshen." Sometimes I see them called the "first" and "second" Dunlap tornadoes but, either way, Sunnyside was probably stronger than "Midway" (or "Goshen").

Well, let's start with the obvious...

Pittsfield-Strongsville and Sunnyside just WERE F5s. I just don't know what else a tornado is supposed to do:
- Absolute obliteration of reasonably well-built houses complete with the ol' "clean sweep" - check
- Wind-rowing and granulation - check
- Horrendous mangling of vehicles - check
- Scouring of the grass - check

It just exudes F5. Now, did either debark trees? That I don't remember or know. Probably, though.

I would LOVE to know if someone can find out WHY those two were downgraded. Can you imagine if this forum had been around back then? We'd be going crazy, and I think justly so!

As for the rest...

I have no idea if Tipton and Grand Rapids were F5 or not. I've never seen pictures of either till today.


I lean towards F5 for pretty much all of these, every single one of which, to my knowledge, cleanly swept at LEAST one home per records:
Rainbow Lake, IN (completely devastated an Amish community as I recall)
Lebanon-Sheridan, IN (plenty of debarking and granulation)
Coldwater Lake, MI x1 (reportedly achieved scouring, tree debarking, wind-rowing (into a lake!), and clean sweeps)
Toledo, OH (did plenty of clean sweeps)
Kokomo-Greentown, IN (more debarking, granulation, clean sweeps, etc - devastated Russiaville utterly)
Of these, from everything I've read, I'm probably the least confident about Toledo, personally, but I think it met the standard. I'm open to alternative opinions about any of them, however!

Now, I admit I don't know the quality standards of the cleanly swept homes. But since all also had substantially extremel context, you get the idea.

Tornadoes that weren't F5 but were nevertheless underrated .... quite a few!
Lake Como, WI - this, if I'm not mistaken, was the one that destroyed a house at AT LEAST F4 damage but was rated, somehow, F1 or something like that. Very well could have been a typo. I THINK it was at Lake Como.
There was also an (official) F2 in the vicinity of Watertown, WI that was almost certainly badly underrated. There were substantial posts about both of these WI tornadoes way deep in the Significant Tornadoes Thread. From this article, we read that at least one house suffered extreme destruction (http://www.watertownhistory.org/ARTICLES/Tornado_1965.htm)

"The entire four-year old three-bedroom home was lifted from the foundation above Mrs. Conley’s head as she came down the stairs, Conley said. It landed in a splintered heap about 50 feet away. A home owned by the Jack Wollins on county trunk Y, just north of Conleys, was ripped to bits with some of the debris tossed over a wide area."

That sure sounds violent.

Finally, La Paz and Wanatah, both were F4s in my opinion.

What gets me is how virtually every tornado that day was either "obviously an F5" or "somewhere in between very, very high-end F4 or 'low-end' F5." It's simply staggering. You were either not getting a tornado on top of you that day or getting an unmitigated monster.

Officially, this outbreak produced 15 F4s and 5 F3s. Here's what I have:

DEAD certain F5s (2): Pittsfield, OH; Dunlap (Sunnyside), IN
Other, most likely F5s (5): see above
F4s (15):
Indiana (5): La Paz (officially F3), Wanatah (officially F3), Rossville-Mulberry vicinity, Berne (also in Ohio), Goshen (Midway)
Ohio (3): Rockaway (officially F3), Swanders, Beaverdam/Allen County
Michigan (3): Coldwater Lake #2, Grand Rapids (possibly F5?), Shiawassee County north of Lansing
Wisconsin (2): Lake Como and Watertown
Illinois (1): Crystal Lake
Iowa (1): Tipton

Someone else on this forum once essentially labeled this outbreak the 4/27/11 of the Midwest and I think that's more than apt.


My sources are: reading the Storm Stalker blog entry at least a half dozen times (for some reason, this outbreak fascinates me like no other) and various other local newspaper articles. To be honest, I apologize my post isn't more rigorous. I used to have more detailed notes on some of these tornadoes.

Real question is, how many of the "F1s and F2s" were actually more significant? What a crazy, crazy outbreak this was. I assume that people were just not prepared in 1965 to adequately rate a true super outbreak.

Rather than filling this post with pictures, I recommend the Storm Stalker entry for most pictures: https://stormstalker.wordpress.com/2013/01/05/1965-palm-sunday/

 

[TH2002]

All three of these homes from the goldsby tornado should have been rated EF5. No questions asked. The last one especially with the extreme contextuals is the one with 18 inch bolt spacing. The other two had bolt spacing of 48 inches. And we’re all three generally very well built. The first of these, which is the last one hit as the tornado was roping out. Was built by a construction engineer who built the home with tornado resistance in mind.

To be entirely fair, in the case of the third one it was reliably documented that a mobile home frame had smashed into the house during the tornado. Not denying that the tornado was more than likely at EF5 intensity in that area based on the scouring and debarking, and I typically hate the "debris loading" argument - but for once, I think there's some validity there.

With that said, the other homes should have absolutely been rated EF5, full stop.

The home swept away in Oak Grove should should be worthy of EF5 for the Hackleburg tornado, at the very least.

Nope. These days it would instantly be ruled out as an EF5 candidate based on the fact that it was (at least partially) on a concrete block foundation.

I honestly think a home being on a block foundation should NOT be an instant disqualifier for an EF5 rating, but based on how surveys have changed post-2013 it would not be rated as such.

 

[ColdFront]

Nope. These days it would instantly be ruled out as an EF5 candidate based on the fact that it was (at least partially) on a concrete block foundation.

I honestly think a home being on a block foundation should NOT be an instant disqualifier for an EF5 rating, but based on how surveys have changed post-2013 it would not be rated as such.

Is this the home in question in Oak Grove?

 

[Tomcats Forever!]

Is this the home in question in Oak Grove?

View attachment 39596

Was that the same location where the storm shelter was destroyed?

 

[ColdFront]

Was that the same location where the storm shelter was destroyed?

I don’t think so. Unfortunately, the man that owned this home wasn’t there during the tornado, but his grandson and grandson’s wife lived nearby in a trailer and sheltered in the home when it was swept away.

 

[Ozonelayer]

So far what I'm seeing is that Smithville and Rainsville would likely be rated EF-5, Hackleburg high end EF-4, and Philidelphia mid-high end EF-4.

 

[ColdFront]

So far what I'm seeing is that Smithville and Rainsville would likely be rated EF-5, Hackleburg high end EF-4, and Philidelphia mid-high end EF-4.

Rainsville would depend on the office IMHO. Any John Robinson type would focus on the construction, the trees standing nearby, and completely ignore contextual damage.

We have gotten to a point in the EF scale where they won’t even consider a 5 unless a well built home with above average construction is swept away first. If there’s high end extreme contextuals but a home had some missing anchors or washers, it’s probably still getting a 4. Like Matador.

I believe @buckeye05 stated that a few homes in Moore were missing washers or something, but OUN correctly still gave it a 5 because the contextual damage was so extreme it wouldn’t have mattered for the home even if they had been present. To me that’s good application of the scale.

 

[buckeye05]

Rainsville would depend on the office IMHO. Any John Robinson type would focus on the construction, the trees standing nearby, and completely ignore contextual damage.

We have gotten to a point in the EF scale where they won’t even consider a 5 unless a well built home with above average construction is swept away first. If there’s high end extreme contextuals but a home had some missing anchors or washers, it’s probably still getting a 4. Like Matador.

I believe @buckeye05 stated that a few homes in Moore were missing washers or something, but OUN correctly still gave it a 5 because the contextual damage was so extreme it wouldn’t have mattered for the home even if they had been present. To me that’s good application of the scale.

In Moore it was the fact that the wall stud connections at some homes utilized the weaker “straight nail” method rather than the stronger “toe nail” method. Regardless, the same overarching sentiment applies: Factoring in context is important because construction alone doesn’t always tell the whole story, and there’s a fine line between factoring in structural flaws and just plain nit-picking. Many surveyors cross that line, but the Moore survey did not.

 

[buckeye05]

So far what I'm seeing is that Smithville and Rainsville would likely be rated EF-5, Hackleburg high end EF-4, and Philidelphia mid-high end EF-4.

Nah, Rainsville is more questionable than Hackleburg so I’d say that’s backwards. Hackleburg did obliterate well-built “slab and bolt” type structures. Rainsville did not. As a result, Rainsville and Philadelphia are the two most likely to end up on the proverbial chopping block under modern day scrutiny. Especially Philadelphia after what happened with the Mauk, GA EF1 back in 2022.

 

[slenker]

Nah, Rainsville is more questionable than Hackleburg so I’d say that’s backwards. Hackleburg did obliterate well-built “slab and bolt” type structures. Rainsville did not. As a result, Rainsville and Philadelphia are the two most likely to end up on the proverbial chopping block under modern day scrutiny. Especially Philadelphia after what happened with the Mauk, GA EF1 back in 2022.

I'm curious about the Mauk, GA 2022 damage now. Did it scour the ground in a similar way? Because if so, I would be very interested to see that. I've always been under the impression that the gouge-scouring done by Philadelphia was extraordinarily violent, and it did coincide with some extreme damage outside of just the scouring too, like the double-wide mobile home being hurled 300 yards in a single toss and the large tree completely debarked + tossed ~35 yards away after being debarked.

 

[buckeye05]

I'm curious about the Mauk, GA 2022 damage now. Did it scour the ground in a similar way? Because if so, I would be very interested to see that. I've always been under the impression that the gouge-scouring done by Philadelphia was extraordinarily violent, and it did coincide with some extreme damage outside of just the scouring too, like the double-wide mobile home being hurled 300 yards in a single toss and the large tree completely debarked + tossed ~35 yards away after being debarked.

Yes, the Mauk, GA EF1 produced that same deep, “chunky” type of ground scouring that is sometimes referred to as “trenching”. The Mauk tornado was not strong, with the remaining damage consisting of downed trees, destroyed outbuildings, and roof damage to homes. Yet it completely tore up the ground. I infer that the composition of the ground and its saturation level resulted in what we see below, rather than it being caused by extreme winds. Now just imagine if a high-end EF3 or EF4 tornado moved across this same field instead of an EF1.


Later that same year, a similar thing happened near Clarks, LA. This tornado was stronger, producing low-end EF3 damage as it snapped and partially debarked pine trees, and destroyed mobile homes. However it again, produced trenching in an open field, despite not being violent.


These two tornadoes have forced me to completely rethink my opinion on trenching. Not too long ago, I think I saw someone refer to deep trenching as one of the most reliable EF5 indicators. A couple years ago, I would have agreed. But now I can’t agree with that statement at all. Sometimes tornado damage proves you wrong and forces you to completely rethink long-held opinions.

While on the topic of certain tornadoes that forced me to rethink things, the 2024 Hancock County, WV has forced me to rethink the minimum possible intensity required to cause severe denuding and debarking. Typically, you only see significant debarking begin to occur in the high-end EF3 to low-end EF4 range. I used to challenge people to find me pics of severe debarking on properties where the structural damage was well below that intensity level. Then the Hancock County tornado happened and made me eat crow. It was an EF2. This is NOT the kind of tree damage that is typically associated with an EF2, but the this tornado proves that it can happen, even if it’s an exception to the norm.

 

[buckeye05]

With all that said, I do agree that Philadelphia, MS was extremely violent and very likely an EF5. It’s just that trenching can’t be used as a “slam dunk” EF5 indicator like previously thought.

When it comes to ground scouring, I have found that the type consistently associated with the most violent tornadoes is less dramatic in appearance. The kind I’m talking about is where all the grass and surface vegetation is cleanly removed, leaving a smooth swath of partially or completely bare soil. This type of scouring occurred in Bridge Creek-Moore, Moore, El Reno-Piedmont, Smithville, Chickasha-Blanchard, Rochelle, Vilonia, Guin, Jarrell, and several others, and I have never seen it happen with tornadoes that weren’t high-end events (with exceptions where the tornado was definitely underrated, like Westminster, TX 2006).

 

[Shakespeare 2016]

With all that said, I do agree that the Philadelphia, MS was extremely violent and very likely an EF5. It’s just that trenching can’t be used as a “slam dunk” EF5 indicator like previously thought.

When it comes to ground scouring, I have found that the type consistently associated with the most violent tornadoes is less dramatic in appearance. The kind I’m talking about is where all the grass and surface vegetation is cleanly removed, leaving a smooth swath of partially or completely bare soil. This type of scouring occurred in Bridge Creek-Moore, Moore, El Reno-Piedmont, Smithville, Chickasha-Blanchard, Rochelle, Vilonia, Guin, Jarrell, and several others, and I have never seen it happen with tornadoes that weren’t high-end events (with exceptions where the tornado was definitely underrated, like Westminster, TX 2006).

I understand what your saying. It makes me wonder if it has something to do with what you are talking about or multiple vertices. As far as the Westminster 2006 tornado it should have been rated high-end F4 and possibly even F5. What that tornado did to things was not normal.

 

[tornado examiner]

When talking about tougher plains clay soil and lawn grass it’s pretty much a requirement for a tornado to be extremely violent for major scouring to occur to that.
(Matador cough cough)

 

[buckeye05]

Yes Matador also produced that type of impressive scouring I was talking about in my second post above. Falls into the same category as Westminster, where the event was very high-end but was grotesquely underrated.

 

[pohnpei]

Yes, the Mauk, GA EF1 produced that same deep, “chunky” type of ground scouring that it sometimes referred to as “trenching”. The Mauk tornado was not strong, with the remaining damage consisting of downed trees, destroyed outbuildings, and roof damage to homes. Yet it completely tore up the ground. I infer that the composition of the ground and its saturation level resulted in what we see below, rather than it being caused by extreme winds. Now just imagine if a high-end EF3 or EF4 tornado moved across this same field instead of an EF1.
View attachment 39630

Later that same year, a similar thing happened near Clarks, LA. This tornado was stronger, producing low-end EF3 damage as it snapped and partially debarked pine trees, and destroyed mobile homes. However it again, produced trenching in an open field, despite not being violent.
View attachment 39631

These two tornadoes have forced me to completely rethink my opinion on trenching. Not too long ago, I think I saw someone refer to deep trenching as one of the most reliable EF5 indicators. A couple years ago, I would have agreed. But now I can’t agree with that statement at all. Sometimes tornado damage proves you wrong and forces you to completely rethink long-held opinions.

While on the topic of certain tornadoes that forced me to rethink things, the 2024 Hancock County, WV has forced me to rethink the minimum possible intensity required to cause severe denuding and debarking. Typically, you only see significant debarking begin to occur in the high-end EF3 to low-end EF4 range. I used to challenge people to find me pics of severe debarking on properties where the structural damage was well below that intensity level. Then the Hancock County tornado happened and made me eat crow. It was an EF2. This is NOT the kind of tree damage that is typically associated with an EF2, but the this tornado proves that it can happen, even if it’s an exception to the norm.
View attachment 39632
View attachment 39633

Yes, an EF2 tornado can, under certain circumstances, also cause debarking or vehicle twisting damage. This truly highlights the inherent uncertainty in these indicators. These damage indicators are referred to as "contextual damage" precisely because they must occur in sufficient quantity to hold value for intensity assessment. A somewhat imperfect analogy would be that the property of "wetness" only emerges when there are enough water droplets. Similarly, for these specific contextual indicators—whether it's widespread debarking, vehicle mangling, or debris granulation—the characteristics of a violent tornado only emerge when they appear in significant numbers.

We can roughly differentiate tornado intensity based on the prevalence and extremity of these features, but it remains difficult to rely on them to determine actual wind speeds. The reason these indicators still hold value in intensity assessment is that structural damage—which theoretically could directly correlate with wind speeds—is often unreliable due to the poor construction quality of many homes in the U.S. In violent tornadoes, house damage frequently fails not only to distinguish between closely ranked intensity levels (e.g., high-end EF3 vs. low-end EF4) but also to provide meaningful wind speed estimates (since many homes are completely leveled even by EF3 tornadoes).